Is it weird for a 19 year old to be best friends with a 16 year old?

Alright so I'm 19, turning 20 in February. My best friend I grew up with, he's 16, 17 just after I turn 20. His brother is my age, but him and I clicked better. I sometimes party with him and his friends, and I just keep thinking it might be a bit weird with our age gap. We both are like the same person, very close and we just have a ton of fun together. I recently just made a friend through a random encounter and he's also 16, and him and I are starting to become good friends, even though we've only known each other a couple months. What do y'all see?