Twisted,
Have you had orientation yet? If not, ask the person/people leading your group a few questions or even if you can check it out while on campus. With as much $$$ as you, your folks, and maybe Uncle Sam is helping fork out for your dorm room, it's a more than fair question. If it's a dorm they don't need during summer and shut it down, a visit might be impossible...just have to ask and see what is said.
I just finished two years of dorm life and will be living off-campus this fall. It does have its pros and cons, but if you're flexible and/or out-going, I think you'll like it overall. If you are extremely shy and take a while to open up, it may not be as much fun as it could be.
As far as shower etiquette goes, I'd say start out conservatively and then go from there. Take a bit of time to see what is appropriate for the floor of guys you live with, first. It's not that you should hide your body, but it can be easier to go with the floor culture on that kind of stuff than against it. My first year group of floor mates was the more conservative kind, the "robe-wearers" if you will. The second year group was more "ehh, who cares?" when it came to robes and towels.
Anyway, good luck, study hard, and party when needed