No, I’m sorry, I don’t know this fandom, but I read it, and it seems okay.
What does squicky mean? It’s not so odd, though, I think, if she really is one hundred, though it would probably be hard, staying fifteen -- appearance-wise, in any case -- her whole life/death, in relationships, and other things, because of the legalities. She couldn’t drive a car, if she ever wanted to, or buy certain items -- spray paint, knives? -- or open a bank account or sign up for a library card without a legal guardian -- assuming, of course, that she would want to do any of these things.
I was wondering though, if she’s a vampire, and vampires have a degree of mind control -- or whatever it is -- then perhaps she could do something to cloud people’s perception of her age/appearance?
Oh well... Have a nice day!