talk to the other girls in your house, dorm, suite, or however your housing is - see how they feel about living in and if they shared any of the same concerns before going in. i think it would probably be a good thing, though. if it doesn't work out, you can always move out after the semester is over. i've had my own, huge room for years now, but i still can't wait to live in the DZ house! think of it as an adventure...
also, do you know of anyone that you think you could get along with as a roommate? i mean, sisters are one thing, but there are some girls that are my closest friends that i could not STAND to share a close-living-space with - at least not if i was expected to keep my sanity.