Boobs

I know I have big boobs and I know a lot of the guys in my school like them unfortunately but they always stare? Like I'll look at their face and they'll be starting at my boobs and then they look at my face and just smile like its normal ? At first I thought I was just thinking they were staring at them but my girls tell me they do a lot so it's cinfirmed and don't get me wrong, maybe 1 or 2 of the guys I don't mind having a quick look but if they get creepy I do mind, I do mind all the others though as I hardly know them if that makes any sense. Why do they JUSR stare???!!?!!?!