Not sure if I should drink a little or not?

So today a friend of mine invited me to her house party. It's celebrate her birthday and all she wants is alcohol. I'm quite scared because I've never drunk before and I'm actually not even allowed to and it's my first house party btw. The thing is, I'm not really fond of the idea of getting drunk or drinking at all. I'd be fine with maybe taking a sip or having one drink. I'm a Christian, which also makes this situation worse. I still want to go to the party but I'm scared that I'll get tempted to drink smth. There are a few people in my class who are also going and I'm hoping so badly that one of them decides not to drink. Currently I'm 15 and it's legal at 16, so I'm really torn between drinking a little or drinking nothing at all. I know that if I don't drink anything they will just tell me I'm a party bummer and all that. What should I do?