I'm going to a Popular High school Party?!
Answers:
.....These people sound like jerks, you should find friends that actually want to be with you. Why go to a party where you aren't wanted? Sounds horrible.
IF for whatever reason you just NEED to be with these idiots, and feel the need to be with the popular kids, then you're just going to have to stand up for yourself. Walk into the party like you belong there and don't take sh** from anyone. Don't walk in nervous with your eyes staring at the ground - don't let them see you're scared. Find your friend that's throwing the party, and hopefully if he's a good guy he'll introduce you to people or hand you a beer or something and you'll be in.