Immature kids

Lately I've been analysing a lot of people and I realized a lot of kids who are my age (16-17-18) are extremely immature for they're age. Now I mean like they yell random things in class and stuff. I just find it weird how I've been in school with them for like 4 plus years and they're still annoying me. I thought it was me, but then I realized maybe it wasn't when everyone else was like giving them sarcastic looks. I'm kinda glad I'm not the only one who thinks they're immature, I would feel kinda mean :\