My advice, stop talking about sex. Most women are shy when it comes to talking about it, unless they are total slut bags...which is totally cool too.
Focus on turning her on, seduce her.
Have fun little games like asking her to wear something naughty for you, or to send you a sexy picture, etc. Use this method to get her thinking about sex, without actually doing it. Remember, anticipation is one hell of an aphrodisiac.
Make her feel comfortable with the IDEA of sex...with YOU.
Women are more turned on by the IDEA of sex than the act itself. Use this to your advantage by planting thoughts into her head (i.e., the games i mentioned above).
It's o.k. if she thinks you were a hoe with woman, that means when things start to happen, she will try and 'out sex' the other girls from your past.
The next time you guys are together and things start to get hot and heavy, STOP. Make her think YOU are not in the mood, in other words...take control of the dynamic. I'm sure you are getting tired of her being the one that determines if sex happens or not...right? If you keep this up long enough, along with getting her turned on, she will be the one ripping your clothes off.
Hopefully this helped some.