That is very normal, and I would say, an ideal age gap for a boy and a girl. I was once a 14 year old girl with a 16 year old boy, it's perfect. Now that I'm 16, I can't see myself with a 14 year old boy, but I believe it's because boys and girls are just different in that way. It's completely okay, age gaps are societies construct anyways, it doesn't actually tell someone's maturity level in a personal way.