It sounds like you've got things figured out. Good for you. Yes, there are those that cause more drama, but sometimes, they make the best friends in school. You will know what's right for you and who you can get along with. If her behavior is negatively affecting you, you can choose to talk to her or distance yourself a little. If her behavior is bothering others, that's their problem.
There are two women in my class that annoy everyone. And, I mean everyone. One asks a hundred questions and it's tough to get through a lecture with her. The other has all the answers, even correcting the instructors and loves the sound of her own voice. It took me an entire semester to agree with what everyone was saying about them. I have decided to get to know the woman who asks all the questions all the time. I know she's annoying, but we have clinicals together this semester, and everyone has made her an outcast. I feel bad for her and hope to help her a little if I can (not that I'll be able to answer all her questions, but I'll try).
We are down to 61 people in our second semester and everyone is just different. Some of our personalities work really well together and some don't. It's okay.
And, just so you know, I was like you and had my books months before school started. Guess what, I didn't open a book my entire first semester. Not once. Of course, I'm not recommending this way of doing things, but it won't be your friends demise. As long as she's getting it together now, she'll probably be fine.