
I know Yakumo is young, but exactly how old is he? I don't think that I am remembering that I ever saw a reference to his actual age other than young or college age. If anyone has this answer, thank you from the bottom of my little Yakumo adoring heart.

His exact age is never mentioned, but I think he's likely 19, give or take a year. Shima says he can start college right away which means he's at least 18. Shima also calls him a child though, and the age of majority in Japan is 20, so by that definition he's 19 at the oldest. If he calls him a child simply because of their large age gap, then it's possible he's above 19, but based on his behavior and appearance he can't be much older than that.
Looking forward to seeing how this plays out! I have a sinking feeling in the pit of my stomach, but can't stand the wait!