Just try not to be nervous and have fun! It sounds like he's interested, otherwise you wouldn't be talking and he wouldn't have asked you out! And if he doesn't figure out what a great girl you are, then he's not worth your time and you'll find someone so much better!!
(although I'm not sure if I'm the best on to be giving advice lately because the last five guys that have shown interest in me have either been married, had a girlfriend, or told me that they weren't ready for the relationship we had after we hung out for one night. I hadn't realized that hanging out once qualifies for a relationship!)