Teenager kid

I don’t know if being a teenager is coming to kids too early. My kid is going to be 11 years old next week, he’s my chill, very friendly and kind kid. The last couple of months he’s been telling me a lot about a girl with him at school.  I don’t know what kind of feelings he has for her exactly.
He will say being with her makes him happy, and if I ask him what does she mean to you he says it’s the first time that a girl likes him and plays with him at school.
I am just so afraid that is taking a lot of his attention at school and he’s having a hard time getting good grades like before.

I need help with this please.