@Madcat6204
If you look back at the previous chapters, it's pretty damn fucking obvious she's not aging at a human rate. Chronologically, her body may be that age perhaps (Her age hasn't actually been stated from what I can tell). But mentally it wasn't since she awakened to her memories. And it now sure as hell isn't physically.
It's not even a case of art drift (if that could even happen that quickly). Check Page 2 of Chapter 1 and then Page 11
Not really 100% sure these links will work, but at worst just gets caught in a filter/broken due to database changes or something:
https://s2.mangadex.org/data/928f7f29feac62271a48598fc00adb70/x2.png
https://s2.mangadex.org/data/928f7f29feac62271a48598fc00adb70/x11.png