Will they let me p?

LEGALLY, you are NOT an adult, you are still a minor child. That's what matters here. If you must by law be 18 to do this or that, until your 18th birthday, forget it. If you must legally be 21 to do this or that, until your 21st birthday, forget it. And it is up to you to prove you fulfill the legal requirements. If you try to use fake, false, forged, stolen, or "borrowed" ID - you go to jail.