Hi Bell, welcome to the forums!
I went into college feeling the same as you 6 years ago. I just graduated last month. I didn't know anyone at my college and my first year was quite the learning experience...in both good and bad ways, but luckily mostly good! I had a lot of social anxiety issues but I was able to work on them over time...Here's some advice that I hope is helpful to you:
1) Do you have friends or know anyone who is going to your college too? That's always a good backup to have for encouragement and support. If not, keep in touch with your friends so you don't feel so alone, which is probably common sense because of course you want to stay in touch with your friends regardless

2) Join a club (or 2 or 3!) that strikes your interest. Most likely this will have people of similar personalities and interests, which will make it less awkward, and you'll get new friends out of it. I met ALL of my college friends through clubs and organizations

3) Sign up for counseling. Most schools offer free counseling services to their students. I did this and it worked wonders for me, my anxiety, and my depression...it made me more confident, more willing to participate in group classroom activities, and have better relationships with professors. students, staff, etc. My only regret is that I didn't do it sooner - I missed out on a lot of good times.
4) Stay away from drugs and excessive alcohol intake. It's okay to drink socially now and then, and to drink responsibly, but I've found that drinking like a crazy party girl only made my depression and anxiety worse...and I never really drank that much to begin with! But the times that I did made me feel worse. You don't need alcohol to be social anyway, trust me!
5) As for roomates, I wouldn't worry so much about that. I've had good roomates, so-so roomates, and terrible roomates...and honestly? You should only be worrying about two things: Noise and Cleanliness. A roomate should be relatively clean and not incredibly loud. I've found it doesn't matter so much what they think of you than more of can you two peacefully live together. After 6 years, I only had 2 roomates that I moved out of the room after 1 semester, because they were just ridiculously rude and out of their minds...for the most part though, I've had decent experiences and little problems.
I've found most roomate issues can be solved early on by talking about your preferences and how you BOTH can work together to meet a mutal compromise. Don't let her push you around just as much as you can't push her around. Talk about morning, afternoon, night routines - what time do you both go to bed? what time do you wake up? what about tv and music noise, what's acceptable and until what time? What's "clean" for her and what's "clean" for you? How do you feel about significant others sleeping over? How do you feel about parties in the room? This can decrease a lot of anxiety and awkwardness; cause you'll be sharing this room all year after all :winking0008 I hope that makes sense. Residence advisors should also be in your building to help you sort out issues if they do arise, and in my experience, that's been pretty rare to see it get to that point.
Good luck and have fun!!!