You could get one of those electronic ones (sorry don't know what they're called) and plug headphones in? Unless you actually want a proper drum kit, these could be quite useful
Edit: i'm so confused, did you change the title, or did I completely misread your post If you had one of these, and headphones, I can't see what the issue would be
Ask your flatmates if there's any particular time of day they'd rather you didn't play at, work out what time will bother the least people and stick to playing then.
By the way rooms in halls can be pretty small, are you sure there'll even be room for your kit?
I think it would be fine. Obviously let your flatmates know that you've got them, it's just courteous isn't it, and I can't imagine they'd have any problems.
There was a guy in my halls who brought an actual drum kit with him. Needless to say he wasn't well liked D: I think you'll be perfectly fine with yours.