You ought to go and start learning to be in a social environment without drinking. If you don't you will find yourself in a great many similar situations as you get older and it's better that you learn lessons such as these early.
If you don't wish to drink then don't, say it firmly if people insist. A guy I once hung out with a few times was tee-total said to me that he didn't need to drink to enjoy himself as much as everyone else, which was totally true, he was outgoing and interesting to talk to. He also used to order really flamboyant fruit cocktails, think Del Boy without the alcohol, which used to draw attention to the fact that he was still interacting and having fun without alcohol.
You should go for it, and make people wish they were half as cool as you were even with after a drink for confidence.