Look people get so hung up on the "first time". The way i see it is you have a great oppertunity here. if it doesnt turn into anything more so be it. but when you do finally find that someone special you will know your way around, and trust me that is worth something.
in 5 years time you will kick yourself for not taking the oppertunity.
my advice
1) use protection. dont want to be paying for a kid for the next 18 years.
2) Do some preperation, never go out with a loaded weapon. (theres something about mary)
3) enjoy it dont rush it, have fun. Sex is not meant to be serious it is about both (some times more) parties enjoying it.