Fore-play is the most important part for first timers. A few tips:
Remember, girls nipples are a lot less sensitive than guys nipples because babies have to chomp down on them, so sucking on them and caressing them with your tongue won't do much. Make sure you bite them quite hard. Don't hold back, and always bite a little harder than you think you should or it will do nothing.
Obviously lube is important, so lube up your fingers, and before you stick it in put your fingers in her vagina and arse. She won't be expecting you to put a finger in the arse and she will LOVE it. Really put it in her arsehole at least double knuckle deep and watch her eyes light up with pleasure. She will be begging for you to fuck her.
Another trick I have learnt is, before you put it in, slap her (not too hard, but enough to make a slapping sound) just above the hole of her vagina 2 or 3 times. About half your hand should be amongst the pubic hair. Girls love this, and it is actually quite a tough area and won't cause them any pain as that area is made tough for child birth.
This should all get her in the mood and make your first time a whole lot awkward.
good luck champ!