@oxtna
If you actually read this thing, you'd notice that it says he's a middle age office worker, when he's introduced. Middle age is between 40 and 60, and she's in high school. So, yes, he's more than double her age.
@Nightwave
Oh whoops. I got US high school freshmen mixed up with Japanese high school freshmen.
But you have a couple of things incorrect, as well. A legal adult in Japan was 20, when this was written (it's 18 now), but if you're still under the age of 20, you need your parent's permission to get married. Which would mean she'd have to tell her parents she's been fucking a 40 year old, which would throw him in jail, because it's still VERY illegal for anyone over 20 to have penetrative sex (which they absolutely did. multiple times.) with anyone under 18, which she very much is.
tl;dr: she's still a minor and he's still a pedo. Nothing's changed.