Since the age gap is about 5/6, and if we were to guess her younger age as somewhere from 6-10 ... And they didn't say how long the time skip was(tho I want to say ten year skip at most, six at least)
I'd say she's about 18/early 20s and he's maybe 24/5?
They mentioned she is small for her age and needs to grow, and I'd say she kinda looks 16/17.. so she's probably actually a little older than that.
Wish they gave actual ages and time frames. They made him look pretty buff at his early age already so it's hard to tell.

I don’t know why the age gap is such a big concern here. She’s coming of age soon, and they haven’t even done anything romantic yet.