Conclusion
I assured Jenny that, no, she was not crazy. But I also pointed out to her that she was a confused young girl, too young to be carrying on in the way she was. I told her that there would be plenty of time, when she was older and more mature, for sexual experimentation. I pointed out that, at her age, education was a very important thing.
I suggested that she try to hold off for awhile on her sexual encounters, and I asked her if she could have her boyfriend, Dave, give me a call, at which time I would inform him that he may be seriously affecting a young, impressionable girl, and that he should cool it with her a bit, maybe find someone more his age.
I also would get in touch with Jenny's parents. It seemed to me that family counseling was what was needed in this case, taking into account what had set off Jennifer's behavior.
I was sure that, given the patient's young age, and the fact that she was reasonably normal and well-adjusted, it would not take long to have her back on the right track.