There's no specific date number you should kiss her on. Kiss her when the time feels right. When that is, varies from person to person. What you should be doing however, is letting it be known what you have a very clear interest for it. Compliment her. Flirt. Hold her hand. Hold the door for her. Show indications that you want to be more than a friend.
Just kiss her when it feels right, man. I've been on dates where we never kissed and with my current boyfriend I kissed him before the first date. If it feels like the natural thing to do, do it. If it feels like something that would be forced or unwanted, don't do it.