A girl said this to me last night at a party at my house.

I was making out with her earlier then I left her alone to go socialize. When I tried to take her to my room later on she refused to follow saying this to me. Then she tried to put herself between myself and my friend seeing who could give her the attention. As soon as she did that, I basically moved on and acted like she didn't exist. I just want to know why she would say that to me and turn cold when before she was more receptive.