As others have said, be friendly but study alone when that works best for you. At my school, the instructors would not allow us to work on graded assignments alone. We had to be in a group. If you are having a hard time finding a partner, tell the most sympathetic instructor and she/he will probably set you up with a welcoming group. For studying for tests - after your first group assignment, you can ask one of your classmates or group if you can join them or their group to study.
I met one of my dearest friends because both of us had no partners when lab partners were chosen. The teacher put us together because we had no one else. We worked together on everything the rest of the time in nursing school.
I would advise you to always get your part of assignments finished early, have good notes and help others in your group, and DON'T ever make snarky, snide, hateful remarks about anyone in your class to their face or behind their back. Don't do it and call it kidding. If it can hurt feelings or cause someone to be mad, don't say it. Not even to a trusted classmate. If you should get in a group which does these things regularly, ask your instructor to advise you on another group.
Also, don't roll your eyes when anyone is talking (if you are an eye roller). Always take the high road in reactions.
You have the jitters right now. When school gets started everything will be fine. You got this far; you can do it. Congratulations on being accepted. You will be fine.