Sex first time is kinda like learning how to ride a bike.
If your first teacher isn't good, then your going to wind up with some skinned knees... cough...
anywho, all joking aside, it will be kinda lame if both you and the other person are virgins since you will both be wondering, "Is it ok if i do this?" Just go with what ever feels good and it should turn out preaty well depending on the patner.