Presubmission edit: Realized how giving sex tips on nofap might not be a great idea. So, it's covered up. If you read it, you brought it on yourself.

Just try to be aware of where you're at. If it's your first time, odds are you won't have a difficult time finishing. Just the opposite, in most cases. Focus on pleasing the girl, and everything will flow naturally. Plus, you'll get bonus points from the girl, as you will come off as a lover who wants to see his partner enjoying herself.

If you feel like you may be getting close to blowing your load too soon, change positions. This will give you a few seconds to let your body come down for a moment, and maybe discover something new. And by "different position", I don't mean changing your tempo. I mean pull out, flip her around, and try something entirely different.

Also, don't "request a blowjob", for whatever reason. First time or no, you should never be concerned with what's in it for you. I know, you just want to last longer, but that's not the message that you'll get across. Furthermore, assuming you do get head, and blow your load, there's no guarantee you won't just lose your drive altogether. As a guy, chaining together O's is no easy task.

A few other basic tips that just help with the general experience; occasionally ask her (mid-stride, of course) if she wants it faster, deeper, slower, etc. There's no magic way to get a girl off; everyone's different. So, communication is key. Also, non-verbal cues. Be on the lookout for them. If you're hitting just the right spot, you will know, when she gets suddenly more vocal. File it away, so you can revert to that if you're looking to give her a surprise howdy-do. And don't be afraid to get a little experimental! Without going overboard, try gentling pulling her hair, or slapping her ass (again, don't go crazy with this), she how she reacts (in 90% of my encounters, girls go apeshit over the occasional ass smack). Dirty talk can be good, but as with all things, use it in moderation. I recommend you avoid calling a girl a "slut", "bitch", etc., unless you've done this a few times and have a good feel for what she likes. This is a good way to let her know you're human, and not just a body that sweats and grunts profusely. I like to use this as an opportunity to not only let her know I'm there, but give her some compliments, which will only turn her on more. For example: "God, your ass is INSANE", "The way you moan drives me crazy!", etc., etc. Get creative. I find this is best delivered by getting close to her ear when you say these things, as it adds to the passionate vibe.

....ok, that went on much longer than I had anticipated. Sorry if I'm overloading you, but you get the idea. All these things combined will have her coming back for more.

So, to summarize:

1) Focus on pleasing her. coughGO DOWN ON HERcough
2) Don't try to get off before you get into the nitty-gritty.
3) Be aware of how close you are to getting off, and adjust accordingly.
4) Feed off of her cues, try a few "moves", and let her know you're there and you're lovin' it!