lost and confused

Hi everyone I have a huge problem.
I have known this girl for a few years now and we just hung out as friends. Anyway I went on holiday with her and her parents and we had a really good time a few weeks later I asked her if we were more than friends and she said she would need to have a think. I got a call the next day saying that she saw me as more than a friend and that we should give things a go and see what happens.
That was about three months ago and we now see a lot more of each other, at least once every week and we text each other most days. When I see her there is never a moment of silence and we get on so well with each other, when we see each other we talk for more than 5 hours. But there is a problem even though I am crazy about this girl we haven’t kissed. I am 19 and she is 20 I know she has had serious relationships before, but I have never even kissed before, I know that it’s shocking but I just don’t know what to do. When I see her we talk about everything and laugh at each other’s jokes and have a good laugh and we even got to talking about what would happen if we were to get married and stuff like that.
What happens when I drop her off at her house is she says just let me out here and I just end up sitting in the car like a fool while she stands at the car door talking to me. Last time I got out the car she hung around a bit while I took some leaves of the windscreen that were stopping the wipers from working. She then just went over to her doorway and waved me goodbye as I drove off. What is wrong with me, I just can’t do it, I have tried everything and she doesnt even know that i have never kissed before. I mean have I blown it by waiting so long? What must she be thinking I just don’t know what to do? Have I waited so long that we are now just destined to be friends forever? Please help me and tell me how to fix this? What would you be thinking if you were her? Its not like I come across as nervous or anything like that, it just doesn’t happen. This is driving me crazy