Help! I have some questions about a relationship?

Ok, so there is this girl on my swim team who i really like and she likes me. Ive never asked her out or anything because we can do the same things as boyfriend and girlfriend as we can when we are just friends. She is inviting me and a small portion of the swim team to a movie on Friday (tomorrow) and i really want to kiss her. I know that may sound stupid but im 14 and my hormones are sky-rocketing. Should i ask her before hand if she wants to kiss? Or should i just make it a surprise? Or should i just wait? Help please if you can! (PS girls would probably answer this question the best)