She's probably always turning 23, just thought it was interesting to mention.
If they're being reset, she's assumedly always reverted to being 22. Characters don't physically age past the date of a reset, otherwise they'd all be dust. Which means either they age normally until the reset and are reverted, or potentially no one ages at all, but since it's usually a short amount of time, no one notices themselves not aging (probably less likely.) I'm guessing the narrators line is just to highlight how she doesn't care about those things and is odd, and focus on what she's doing with Nao, personally.
Maya Prime is an interesting case because she'd not been reset for so long. She also didn't age though, and we can be 99.9% certain her brain didn't age/develop despite her body not. She doesnt have alzheimer's or something. Even though she's 'super old' (based on how many years she'd been conscious consecutively,) her brain was still the same. So she's really only like 16 still, she just happened to experience thousands of years of time at that age. Still doesn't have a developed adult brain, though. Poor Maya
If my grammar sucks fuck you I'm in the bath
Edit: The interesting thing about Maya is that it shows that even if you're "not reset," your body still is. That, or they really don't age after all cause >simulation or something else
