dude,

just have fun - don't worry - you are around average, and to be honest it is what you do with the girl that counts.

my advice, take your time, enjoy a lot of foreplay, get both of you warmed up and excited!!! enjoy it.

a good way to start is to give each other full body massage, and then explore each others bodies - with both fingers, lips and tongues - spend as long as you possibly can doing this, this will relax you both, and get you both hot for whats to come.

i would say wear a condom, better safe than sorry