So the girls around me no matter who it is always pull up thier pants and pull thier shirt down. I got a feeling they think I'm creepy and I give off bad vibes. Also how do I look at a girls butt without getting caught? And how to not be creepy and give off good vibes and not look at a girls butt for so long.

ah, you're trying to hide that you're looking. that's why girls find you creepy. usually if I look at girls, I have eye contacts and give them smile and they always smile back no matter how old/young they are. of course the smile should look natural. when you have more confidence in yourself, you can start learning how to look at girls' ass lol
but if you want to try, after exchanging a smile, you can stare at her ass smiling, nodding with big body gestures. they'll probably laugh at you and tell you to stop staring but hey, then you can start talking to them.