I don't know how big your class is. I think that's one of the downsides of having a small class because it's not as easy to find a group of people (or someone) you can get along with.
That said, you'll learn some techniques in mental health, if you haven't taken it already. Yes they work on other people besides mental patients (though I think some of these people who are not mental patients should be evaluated for other things, but that's besides the point), and should this person decide to get super confrontational, you won't look dumb, she will.
I can only speak from personal experience, which sounds similar to yours -- I had a falling out with someone my final semester of nursing school
and with whom I thought I was good friends with until, well, I tried being a good friend, and told her she has some unsavory aspects about her personality. I had seen the red flags though: her two-faced attitude towards teachers, her over-confidence in a lot of things, how she bragged about her externship, the patients she took care of, her getting into fights with people over issues that didn't concern her at all, the list goes on. I will never deny that she'll make a wonderful nurse (I think she failed boards), but I would never want her as a coworker.
If you're wondering, she decided to call me 10 hours after our "spat" (I thought the conversation was over) to talk to me about my "comment". Sorry, but I won't be insulted over the phone. I hung up on her, and yeah, other people found out. I can say no one particularly felt bad for her.
It's good you recognize that you want to keep your distance from her, now you just have to act on it. Definitely everything Devon said, and if you're like me who doesn't like to confront people, if possible, try finding another group of friends or associates who don't hang out with her.