A Fujoshi Bitch's manga / #sweet(20)

so heart warming and adorable. but i confuse about their age. because in the graduation ceremony (ch.3 page74) it said they're 18 but why on the last chapter Kojima said he is 15? and in the begining, weren't they talking about having sex in 15 in too fast. and then Nakahara said his first sex on his 15th was an accident and said like it happened in the past so it means at the time they're talking they're already older than 15. but if they're 18 now, it means they're going to be college students but why they need to buy uniforms? i'm so confused. TT^TT whatever, more than anything else, I really love Nakahara's uncle ε=ε=(ノ≧∇≦)ノ he's exactly my type!!! so niceeeeeeeeeeeeee and handsome and reliable and dependable. I really do love him. (≧∀≦)