You need to find off-campus housing. This is only one of the inconveniences/sacrifices you signed up for when you got the snake. If you really believe that you are going to have this snake 20-30 years from now no matter what happens in your life, then this is going to be a good experience for you because it's minor compared to what's probably to come.

You'll probably have to choose between the snake and a boy/girl at some point. Not everyone is going to want to hang out with snakes, and some people won't enter a building where they're housed. What if you're offered a life changing opportunity somewhere along the line and the snake can't go (like, say, going to college)?

Trust me, you aren't going to be able to hide it for the 30 years you think you're going to have it. Even if you could, it's stressful to deal with. I'm sure most of us have done something like what you're considering. In addition to asking how to get away with something like this, you should also be asking what a pain in the ass it is to try to make sure no one finds out. You're going to wonder if your roommate's showing someone when you're in class (he/she probably is). You're going to spend time trying to figure out how to sneak food for it in. Every day, probably several times a day, something about that snake is going to cause you concern or stress or something of the sort. I know, it doesn't seem like a big deal to devote your life to hiding your snake for a year, but these situations will arise again during your lifetime.

I'd suggest off campus housing if you can make it happen. If you can't, then you should at least consider the idea of finding the snake a good more permanent home. Don't put yourself and your friends/roommates through the headache of trying to hide it in a dorm. It's fun for the first week, after that it sucks.