Sweet dude!
Many folk mentioned to verify she is "clean" as she should you... everyone should! Also, verify why (but not in detail just to find out if out of self-esteem issues - that she might have gotten over anyway).
When with a woman that has had numerous partners I take this is a good start. First, it implies that she likes sex. Invariably she now knows how all the basics and knows what pleases her (so just up to me to have fun discovering the nuances of her body).
But there were quit a few sound replies. I have let my little brain, much more powerful too often, think for me and the women that have been around sometimes have too much baggage and the number of lovers reflects it. I do the math however cursory hoping that the number reflects that she had had her share of weekend lovers but that number isn't so high, which to me implies she has had some long term relationships. Single now, but always go into a relationship hoping it will last, thus, the math to see if she has had some long term relationships (hoping I am next).
The point about if the number is excess is well taken. Not sure why, I acknowledge not right thinking, that if I have a male buddy that has been with 50 chicks I want to high five him but if a woman has had Madonna numbers I gag. When I see a picture of Madonna I only see a warm grilled cheese sandwich being openned and throw up in my mouth a little she makes me just sick to my stomach - as does all the celebrisluts like Brittany and Paris.