To begin with, I really like Manga!/SMC Chibiusa a lot.  As such, I do get a lot of thoughts about her as a character and some what ifs.  Unfortunately, I think a lot of my theories and thoughts wouldn't make a decent thread and to cut down on some of it-  I think I'll place some of it here.  (at least the ones related)

Theory: I have a working theory that Chibiusa, once she becomes a full fledge adult, that she'll look older than her mother and spiritual grandmother, Q. Serenity.  

* Explanation:  Ever since we learn that Usagi stops aging at 22yrs old and the fact in the material collections (and in some shots of the manga) Q. Serenity is supposed to look 18yrs old,  I have this idea that Chibiusa would look at least 24-26yrs old when she's a full grown adult. 

I based this idea on how she looked as Black Lady ( and not when she's aged-switch with Usagi).  As Black Lady, she looked like an adult woman who's  at least about the same age as her mother, physically, and was clearly older than Usagi.   I like to make a guess that when she truly come into her own and is queen, that she'll be older like that.  I also like to think that the reason that is, is her proximity to being a person of mixed heritage (being the daughter of the Prince of Earth and the Princess of the moon.).

That her being part Terran/Earthling(what have you. Golden Kingdom royalty), would be the reason for it since people of Earth originally had short life spans and grew up faster. 

I also think this is the reason why Usagi stops aging at 22yrs old. Physically, her body was reborn on earth and she grew normally as humanly possible, but since she became and accepted the role of queen- I think it activated the part of the Silver Crystal that lengthens life expectancy.  (and that's a whole separate theory in itself where I think the life expectancy only lengthens when the holder become an active ruling monarch.)

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Theory:  Kinda ties in with the first and is also an evolving theory- but I theorized that two possibilities exist for Chibiusa that she'll only get to rule for 98yrs, due to the fact that the Silver Crystal only lengthens the lifespan of the Silver Millennium's people to 1000 yrs (with some outliers being added with 1001 to 1010 at max.).  So, unless her parents step down, which I believe they would once they think she can deal with everything, her reign would probably be full but short. 

The other possibility I had in my mind was that because she's accessed a new crystal that's a combination of things too, that she'll actually extend the life expectancy of the Silver Millennium people (or just the royal family) to at least 1500 to 2000. 

Explanation: I based both of these on the previously given information we get from King Endymion in the Black Moon arc and on Chibiusa's Diaries, where in one she and Usagi celebrate their birthday and she reveals that she's 902yrs old (meaning she spent at least a year in the future before returning to the present.). 

I also based the idea of her extending it all, because look at her parents. If Mamoru and Usagi's combined power is amazing enough to be felt all the way through the galaxy that the Starlights felt it, then what would their daughter achieve as she's a combination of both of them and has had proper training?

I figured Chibiusa would have something amazing when she becomes fully grown up.


so, any thoughts?  (I know, they're kinda yeah but it's something I thought about a few times.)

I like your theories overall! I think the idea of her having a short time at the end of her life is a bit tragic but I'm not really against that. But you're right - who knows what might happen with her lifespan considering her unique heritage!

I actually find it kind of hard to visually tell the ages of Naoko's characters, especially in very small ranges of only a few years... she says Q. Serenity looks 18 but if she said she was supposed to look 20-25 or even 30, really..., I'd believe that too XD. That being said, I remembered from manga club that we see an image of future Chibiusa in the Super S arc that isn't the age switch scene...

In case you haven't read it yet, this is quite spoilery...:

I couldn't tell you whether she looks older or younger than Black Lady there. To me she just looks less evil lol. Just figured I'd throw this up for your consideration anyways though~.

Diagnosed wrote:

I like your theories overall! I think the idea of her having a short time at the end of her life is a bit tragic but I'm not really against that. But you're right - who knows what might happen with her lifespan considering her unique heritage!

I actually find it kind of hard to visually tell the ages of Naoko's characters, especially in very small ranges of only a few years... she says Q. Serenity looks 18 but if she said she was supposed to look 20-25 or even 30, really..., I'd believe that too XD. That being said, I remembered from manga club that we see an image of future Chibiusa in the Super S arc that isn't the age switch scene...

In case you haven't read it yet, this is quite spoilery...:

I couldn't tell you whether she looks older or younger than Black Lady there. To me she just looks less evil lol. Just figured I'd throw this up for your consideration anyways though~.

Lol, I know! Naoko's artwork makes it harder to figure out, but (I've read all the mangas way way too many times. xD no spoilers for me.) I've learned to see a pattern in the headshapes she gives them.

Like for younger characters, the bottom half of their faces is still rounded and they tend to have wider eyes a lot.  There's also this thing she does with the lips to denote adults and much smaller or more narrow-ish eyes?  -If that makes sense.-

Like, I can tell the difference between Black Lady and when Chibiusa and Usagi got age-switched. Aside from the blank look in BL's eyes, her face is a little sharper.  While Aged!switched Chibiusa looks younger in a way because it's more rounded. 

But, there is a thing I did also notice in the manga that carries over to both animations:  Any time the girls interact with someone they deem more mature or 'cool'- regardless of their actual age, they tend to look older.  (This happened with Haruka and Michiru.  Small degree in the manga too in Chibiusa's diaries where they were after a vampire and the girl!Vampire looked much older than she actually was.)

-anyway off topic- 

I think in that image, just looking at the headshape?  I'd guess at most maybe...18? (honestly, I don't know. It's the only image we have of her as an older person aside from the splash pages for this arc.) I think 18yrs old is a comfortable age there. 


Also my newer theory: 

Because Chibiusa was able to transform the Silver Crystal into a Pink Crystal, it granted her an extra 1,000 years to live along with the entire earth- giving everyone the total age of 2000yrs.