Why do some virgins think they are superior to nonvirgins?

Ok, so I have just started college a month ago and as you may have guessed I am not a virgin. I have slept with six guys spaced out over a year and a half and my best friend is a virgin. Since going to college we have hooked up with a few people (I haven't slept with any of them, but I did go back to a few of their places) My virgin friend has been saying stuff to me like what you are doing looks really bad and hints that I am a slut. It doesn't make sense because she brings guys back to her dorm all the time, but just doesn't go to there house. Whats the difference? And I have only hooked up with a few guys since coming here, but she has made out with over fifteen guys in the last month! She also recently started trying since coming to college(with a guy she just met when she was drunk) and has done that to three guys so far. I don't understand it. She looks down on me just because I have had when she is really more promiscuous than me. When we talk about it she just says "Well I am a virgin" to justify her behavior. Can anyone explain this to me?