idk if exact ages are mentioned but maybe she's an older teen if not just barely a young adult? tho we got a flashback of OG Jelly and dad and presumably she already 'awakened' to saintess powers then if not 'chosen' by some arbitrary event /given the 'don't treat me like a child' line everytime she gets a headpat is prolly a complex of ppl either seeing her as still young bc she's short or so lol