Geez, you're so selfish. Why do you care if they use some of your stuff or not? They're not gonna break your stuff and most likely, your roommates will also bring some of their stuff that everyone will probably use, so just let them use some of your stuff too. I can't believe you're trying to reject such a prime opportunity in order to better yourself socially, mentally, and maybe even physically. This probably the last chance you'll be able to make friends easily along with improving your own being but you're willing to throw all that away because of god knows what reasons.