Yes, according to a book that may or may not be considered canon. I also created this before that book existed. I like the idea of her being a pegasus though, it's a fun idea. It's always fun imagining things and filling in the holes that show leaves.
Definitely a good point! It's possible though that before, her talent of inspiring love was something that was done verbally (or through actions) and manifested as a castable spell once she became an alicorn. Food for thought!
And you know what, it makes sense. Except I'm not sure whether Luna or Celestia were a pegasus and a unicorn respectively. I'd put Luna down as a unicorn type more than I would Celestia, myself. It's not really clear which of them is more magically adept, the difference between their respective celestial bodies aside. But then again, it's Luna who made the greatest use of weather-altering magic so far (Luna Eclipsed). I certainly agree on Cadence, however. She's a rather earth pony-ish alicorn anyway. She hasn't been flying all that much, anyway. I also have to say that both Luna and Celestia are quite the cuties here. Celestia is all bold and beautiful dawn, and Luna with that somehow alluring gaze and pose... whooee. You managed to preserve the feeling of the characters' design as alicorn in these versions very well. Nicely done.
Wow, thank you for the lengthy comment! I'm glad I can inspire someone to think this much about a piece of my art. I wanted to make sure that each pony, in their pre-alicorn form, would retain their current personality. I think I decided on Celestia being a unicorn mostly because she's the (seemingly) more powerful older sister, and she has a school for gifted unicorns. I could see her power being built off a unicorn base. That is not to say, however, that Luna could not become extremely powerful and adept at magic once she became an alicorn. I guess I just saw Luna as a pegasus that soared through the clouds under gentle moonlight-- plus feathers can add to any character's mystery and allure, I think.
I can definitely see it going the other way as well, like you said. Celestia would certainly make for an amazing sight-- all sunlight and powerful with her giant wings, and Luna quietly in the background with her horn aglow. They also could've both been unicorns, or both pegasi! I think any combination is correct really, I just had fun making them a "trio" set (unicorn, pegasus, Earth pony) because the show seems to play off that balance. That gives the big spoiler that the Hub revealed some interesting implications, if we followed this train of thought! Hmm!
Indeed, it could go either way, or another one entirely. And I certainly see your reasoning behind the choice, and also think that you succeeded and preserved their personal distinctions and traits. But I guess that over the time of their lives, they got so used to wielding both forms of power equally. Luna seems to cast lightning bolts without using her horn, but with her eyes glowing—maybe she uses both the pegasus and the unicorn parts at the same time. Regarding her dreamworld shtick, however, I think it's mostly the domain of her unicorn powers, and given the apparent ease she does it with, she is pretty proficient with it. Celestia seems to love flying quite a lot (even if she's being carried in a chariot) and only really walks indoors, and her active casting and combat stances are both airborne, while Nightmare Moon and Luna seem to even opt for ground-based charging despite their wings. It could speak of their old instinctive preferences. But yes, over the time, the difference has all but disappeared. I actually think Celestia and Luna's case is rather special, since Cadence doesn't seem to be neither as powerful nor as old as them. She aged like a normal pony, at any rate. It may be that Celestia and Luna got their immortality elsewhere, perhaps from their connection with the celestial bodies. But your choice of an earth pony shape for her works well and is justified by her having stayed on the ground with only some memorable exceptions and having not used magic all that extensively, only being somewhere around Shining Armor in terms of power. As for the three subspecies, it used to be a fun thing before Season 3, but with the introduction of the Crystal Ponies, there are now four (even if they all appear to be Earth ponies in crystal form). Three is a nice number, and it's good for things like what you did here. However, hearing people go "alicorn Twilight upsets the cosmic balance of the Mane Six having two members of each subspecies!" is made a bit silly by that. It was a nice thing, but is it really important to have two of each? Nah. It's superficial. Not saying that you declared otherwise, no, but just noting that. And of course, welcome. Thinking a lot is what I do. And this here is a good thing to think about. Plus, I've thought of this before, so it was nice to explore it some more.
Oh, what a good point about Celestia and Luna's instinctive preferences. Hmm! It's really a toss up, huh? I love exploring this sort of thing. I agree on all of this, and Cadence as well.
Now that I think on it-- you're right, Crystal Ponies ARE only Earth-type, aren't they? I suppose then they wouldn't be considered "Earth" at all, really. I wonder what their special power is? Unicorns have magic and telekinesis, Pegasi have flight and weather control, Earth have strength and inherent nature magic. The Crystal Ponies (if we're to consider them an entirely fourth subspecies) appear to be able to channel their love and hope into the Crystal Heart? I wonder if that extends to other abilities, and reflects in Cadence's special talent? (Assuming, that is, that she IS their princess-- I like to think that the evidence is very strong).
That then brings the question about why Cadence has aged normally, and why she seems like a "new" alicorn princess. Is she reincarnated? Was she cursed? She doesn't seem as powerful either, which then brings to mind that she was "made" a princess within recent years (when she was the approximate age that Twilight is now, perhaps?). So THEN I must wonder if there are different stages of Alicorn-ism? Physical/magical changes that take place over time? One slowly grows larger, longer-legged, and more powerful? So then perhaps Celestia and Luna are just older and more "leveled-up" than Cadence and (soon to be) Twilight? Hmm! Well, that was a tangent...
Hmm. I always thought that the Crystal Ponies' magic had to do with the obvious thing, crystals. I'm wondering whether the true Crystal Ponies are actually organic and only appear crystalline, or are they really pony-shaped beings of crystal (obviously, that's rather unlikely). If the latter, then their magic could be that they're actually bucking alive, and that's big enough. But if the former (or in both cases, actually), then I think they can interact with crystals in a different way. All of their buildings and many of their other things are shaped out of crystals, for example: what if to them it's like clouds to pegasi, a material they have great affinity for and can shape however they wish? Raise buildings out of it, create tools and armour, that sort of thing. And of course, aside from that, there's the whole surface-to-orbit-mood-cannon shtick the Empire has. Their magic may have something to do with the way the Empire somehow projects the dominant emotion in its bounds. Having a mood ray that can affect the entire continent as your palace is pretty magical, I'd say—and lends more support to the legitimacy of the term "Empire". They could very well have ruled the land with that sort of ability until Discord came by, and then Celestia and Luna instilled their new order that had the Crystal Empire turned into little more than a part of Equestria.
Yes, it may be that alicorns, too, grow with age. In light of the new canon regarding Princesses and alicorns, it may be that Cadence was made a Princess. I have a somewhat convoluted theory regarding her Princess status and her apparently being "The Crystal Princess!", as one of the Imperials said. I think that when Sombra took over the Crystal Empire (was he a member of the royal family? Was he an outsider? We may never know, sadly, but I sure hope we will), the royal family fled and took refuge in Equestria. Celestia and Luna struck Sombra down, but the Empire disappeared in the process. The Crystal royal family was thus preserved in Equestria and married into the Equestrian royal family (Celestia and Luna are sisters, but they are not the only children of their parents, another bit of headcanon. As for why Cadence and Blueblood are called "niece" and "nephew" of an apparently immortal princess who's at least more than a thousand years old and whose only sister has just come back from the Moon, I can only put it down to tradition of labeling the great-great-great-great-great-~-nephews and -nieces as just "nephew" and "niece"). Then, before the Crystal Empire returned, Celestia was able to determine that it would happen within the lifetime of Cadence (knowing the duration of the spell, or some signs, or some prophecy, something like that) and made sure she would be ready for it by giving her the title of Princess and teaching the necessary skills. And do note that Cadence's hair appears very similar to a "sad" Crystal Pony, but isn't quite there—I take it as a sign of her having distinct Crystal Pony ancestry, but not being a one hundred percent one. This is also a clever ploy on part of Celestia, the master schemer: by letting the Crystal Empire's royal family merge with her own and by instructing and mentoring Cadence and transforming her into an Equestrian-type Princess, she made sure that when it emerged and Sombra was defeated, it was not only of no threat to Equestria, but in fact became a part of the country and a strong asset in maintaining stability, because its ruler would be loyal to her.
So, to sum up, I think that Cadence is a descendant of the Crystal Pony royal family, who aged normally. However, she was chosen by Celestia to become the ruler of the Empire once it reemerged and thus made everything a Princess should be. She became an alicorn somewhere before becoming Twilight's foalsitter, which'd mean somewhere in her teenage years, younger than Twilight is now. However, she's still within what her normal lifespan would be, at least for now. She has grown like a normal mare. It may be that alicorns develop over time, yes. It's still unclear whether they are all immortal or whether Celestia or Luna acquired the trait elsewhere. I always thought the Elements made their Bearers immortal, and did this for Celestia and Luna and now for the Mane girls. If so, then Cadence may not have the trait. However, it may be that alicorns are immortal by nature, or that both hypotheses are in fact correct. I'm going with immortality for all of them, since I love 'em all. In any case, I'm glad that Twilight isn't going to look like Celestia and Luna anytime soon. I love her current shape and I'm happy she gets to keep it. It may even be that every alicorn looks different based on their personal shape, and that Celestia and Luna had a predisposition towards being the way they are (there are normal ponies a lot like Celestia, after all, such as Fleur de Lis).
Basically, alicorns are a ludicrously convoluted topic that has practically no grounds in canon as of yet. I'm happy we'll get at least something explained to us now. Personally, I'm all for doing away with this whole "super-extra special there-can-be-only-two" thing for alicorns. Let's not limit their number, only keep the means of becoming one difficult.
Wow, I really enjoy your theory about Cadence! Good reading, there! I also agree on the "super extra special there can only be two" not being the case anymore. I would indeed rather make becoming one difficult, as opposed to limiting their numbers. But if princesses are made, then does that mean the the child of an alicorn isn't going to be another alicorn? That throws that one brony's awesome genetic explanation that I accepted as headcanon into a wild tailspin. Also, why aren't there any "princes" (male alicorns)? Is it just a matriarchal society, or have we just not seen one yet? I think that could be a really interesting explanation. Either way I'm glad to see more alicorns. Maybe it CAN be a genetic trait (Cadance and Shining Armor might have an alicorn baby), but also given, in the case of Twilight.
And in Twilight's case, I also am glad she gets to keep her shape. If we're going with the "power up over time" perhaps she will grow taller and leaner like the other ones? As she gets to the later stages, she might also get the neat flowy/shiny hair, too! Hmm!