We're kind of in the same boat! This might not be great advice, but remember that you've already been living away from your parents--you know how to take care of yourself and more or less run your own life, which is an excellent place to start. That should give you a real feeling of confidence! There are a lot of people who have trouble with just that.

Also, if you're quiet and artistic, are you going to be in an art program? If not, I'd suggest trying to find activities at your school that speak to your interests and the things you enjoy, so that you can be in an environment you're comfortable in (the art world) while dealing with being around new people. You may even find some folks who are very much like you.

Good luck and best wishes!!