I wanna ask this girl out, im doin it tommorow, last minute advice PLEASE!?

Ok, im 17 turning 18 in a month and there's this girl that works at a grocery store(probably about 19) as the cash-register person, so getting her alone is damn near impossible. She is really beautiful, probably the most beautiful girl I have ever seen and I think I have a pretty good shot with her, but the problem is I have absolutely no affiliation with her at all. We don't have any mutual friends, school, nothing and the only time I ever see her is at the store. I'm thinking of starting up my conversation with her like this; hey I'm Rene and I always wanted to talk to you but never really got the chance. And if she reply's with something along the lines of "why did you wanna talk to me" I'm thinking of saying "because honestly I think you are the most beautiful girl I have ever seen", she says thanks or whatever she says, and then i wan't to tell her; will you go to the movies with me? Will this plan work, if not, any suggestions please?