@aikarosei That doesn't really matter though. Families can be lackadaisical about things that they really shouldn't be.
Not sure what the timeline is in Japan, but it's likely not very different from here in the states, where becoming a lawyer requires at least 7 years of school. Meaning that the guy is at least 25 (unless he got into college early, but even if you take 1 year off it doesn't change much).
He knew her since she was in elementary school (judging by the backpacks), so that means at the latest he would have met her when she was 12.... and he was 19. That's a big fucking yikes no matter how you slice it.