How to make friends and act around a new clroom?

I moved down a learning level in one of my cles. I'm a good girl that tries my hardest at all I do because I want to get into a good college, but I struggle with some cles. I'm now in a lower learning cl, and it's filled with druggies and so called "cool" girls that like causing drama and flirting/touching every guy they talk to. There is one girl that my teacher put me next to, she seems like a good kid, and she's in my homeroom, but I've tried talking to her and she just doesn't want to talk back. I've noticed she is quiet. From her body language, she doesn't seem to care talking to me. My problem is I'm super quiet, I mean, I never know what to say to people or how to act. Well, I have trouble talking to people that I know of from other people, but never actually talked to them. I am better talking to people I don't know at all. So, I don't want to be a loner again, and there are a lot of group work in this cl. How do you act when you are in a cl that you don't know anyone, and when they talk to each other they talk about people that you don't know at all, or stuff you don't care about? what can I do to try to start a conversation with that girl? and I sit in the front row which is a horrible spot to talk to people, and since the teacher's right there. And I already know the guy who sits next to me, and we used to talk a few years ago, but he started smoking with his friends last year, and now he doesn't talk to me or care about anyone except his group of friends now.