There are just some things you can't do properly till your a certain age, drink, smoke, concerts (clubs), cinema..... Just accept it, it's much much more fun when you can do what you want, and know that if anybody says a thing you are always in the right.
Even something as simple as buying a DVD, and knowing that your not going to be asked about your age (even though I've never actually been asked about my age)....
Still the way I see it, not 18 you shouldn't go, accept it and just be glad that when you do get to 18 there will be lodes of other people too young to go