What do i do about meeting my boyfriends friends?

I'm going to this carnival with my boyfriend and his friend and his girlfriend and a big group of his friends will be there too. His friends are all really immature and lively and i really hate people like that. I have to go because I've already promised that i will. I just don't know how to handle them. They haven't met me yet and they'll probably be asking loads of questions. How do i meet them for the first time???