Pleeeease don't turn this into a massive deal. If your first kiss is rubbish, you can be sure the next one will be fabulous. Just relax and go with the flow - good luck chick!
The thing about first kisses is that they don't really happen as one kiss. Immediately after you first kiss, you are going to have your second kiss and then your third......He will want to kiss you more than once.
You have your first kiss when you feel ready - probably after some other physical contact (holding hands perhaps) and when you feel fairly comfortable in each other's company. Relax - once it's happened you will wonder what you were worrying about. :-)
Even though your first kiss will be something you will remember its not gonna be the best have it and move on if its bad dont worry about it there will be that guy who will lift u off your feet soon enufff and if its good be glad and set the bar high!! its nbd really just go with the flow when the time is right it'll come =]