What should I wear on a first date?

One of my bestfriends asked me out. We're going to see "Nightmare on Elm street" on saturday night! It's supposed to be around 15 and sunny. We're going on a double date with one of his friends and his girlfriend. I don't know them at all and would like to be friends with them too. So ya. We're all 14 and in grade 9 in a highschool. I'm REALLy excited. Just some extra details.....I live in Canada Eh? So 15 is pretty nice for us, I'm told I'm all legs, and a 34A for a chest,I'm 5'8 he's 5'9 ...this is just to help ya out! I'm more of a jeans and a tanktop kinda girl, bit of a tomboy. I also have shoulder length dark brown hair (natural) with chin length layersi have pretty tan skin, and i've given up trying to keep track of what color my eyes change to, i wear gles, I love my black fedora, so any ideas for my hair would be nice.....hint hint. lol. I'm rambling now! any help would be really cool!! And yes, I know this has been done TONS! I'm just wanting something more specific for me!