What is an acceptable form of ID to get into a gig, as I don't have a pport?

I have an Oyster card with my photo on it, it doesnt have my DOB on it, but it does have a photograph, and states that I am 14-15. And I also have my birth certificate, although that doesnt have a picture on it obviously, and my surname was changed when I was 2 so I also have my statutory declaration about the name change. To get into the gig, I have to prove I am 14, which I am, but will I have to bring all 3 of these doents along to prove it, and would that even be accepted. Argh help please, because my ticket has already been ordered :S