How do I go for the kiss?

Ok, so for those of you that may have seen my previous question, this girl and i have been talking for about 2 months now and have gone out on 2 dates and hung out once in a group. Tonight we are going out on a 3rd "date". We're going out to get dinner near where she works (because she gets out of work at 8:30 yet for some reason she was still willing to start a date that late, which is different because she normally doesnt do that, but anyways) I am going to go for it no matter what. I have to because I've waited twice (well... ran away once :/) and I just can't do that to myself anymore. I'm very nervous because there is alot riding on this (including her prom which is next friday, my prom which is the tuesday after, an after-prom 3 night weekend on MDW, and not to mention my own emotions) so i REALLY don't wanna **** this up, because things would be super awkward if i did. But I have to do it, because I feel like if i dont go for it now I'll never get it done. There is still part of me that doubts myself and says that she doesn't like me like that, but then again I'm not sure why she would agree to go out alone with me 3 times already if she wasn't interested (and i don't think i've been freind-zoneded just yet, but thats what im tryin to avoid lol). Anyways my question, after this HUGE preface lol, is how to go for the kiss? How do I make her more comfortable throughout the date leading up to it? Remember we are only in high school and going to be in a restaurant probably. Do i go for the kiss at the end of the date or the beginning or or sometime in between? Sorry I sound like such a total newbie with all theze questions, but this is my first real relationship. The only other "action" i ever got was in 8th grade (which doesnt count lol) and some slut that i hooked up with a a party last year (doesnt count to me either cuz their was no feeling to it). So yea... PLZ ANSWER FAST I DONT HAVE MUCH TIME!