The charitable explanation is that her species ages faster, so being a 7-year-old wyrm is like being a 24-year-old human.

That'd be reasonable (if incompatible with the implications elsewhere that she's super old). But given the paranoid "ensure this can't possibly be interpreted as aphobic no matter how much bad faith that would require" reflex, you'd think the author would be more wary about even the potential to be seen as having a Problematic Age Gap!

ETA: let alone an underage Inhuman Monster.