The previous poster has given you some great advice.
The only thing I will add is that I don’t think you should avoid your room because your roommate has friends there. I don’t think you should ask her not to allow her friends to sit on the bed or in your chair. I think it’s pretty common to use those spaces as furniture but when you want and/or need to come “home” go on in, put your stuff down and say, “I need to sit down.” Then join in the conversation and maybe you will feel a little more comfortable with this group over time. Maybe not enough to feel a full connection but enough to be in the “Hey, how’s it going?” category.
Hopefully you will get to know some other students in your classes soon. Sign up for any study groups offered and make casual conversation with those sitting near you.
IMHO I think it takes 3-4 weeks to start feeling comfortable as a freshman.