Okay, my girlfriend wants her "first time" to be good, what do i do?
Make it good
Don't make it awkward, first time hurts to some people. Make it fun and make sure she enjoys it. Be cheesy even, put out rose pedals ;)
Some romantic music and rose pedals
Marry her first!
If your under 18 don't do it, if your not then go slow, it will hurt her a little. Don't just agree to do it make it happen naturally,be fun and romantic to get her In the mood.