I like a guy who is a few months younger than me, is that okay?

I'm (17F) and he is 11 months younger than me (16M), but we both are in same grade (10th).[before you ask me why I'm in 10th while I'm 17, i school my schooling late because I was a quite kid, I started talking late].

We are friends since 4th grade and he was my deskmate in 4th grade (he is a yapper and I'm a quite kid). After lockdown when the school re-opened again in 6th grade, he approached me during lunch and asked, "do you remember me?". I forgot his name and he was taller now (I'm bad at remembering name 😭). Later he walked away then i remembered his name but it was too late, he has walked away.(I should have ran and said it 😭)

Btw, there is more to this story but I'll only post this much.