I just turned 21 this week, and I only recently moved out when I went to college. I know where you are right now. Just make sure to mention that you will take the snake WITH you when you do move out. I don't know how it is in Sweden, but in the U.S. snakes are not allowed in the dorms. I would think about your living arrangements next year.

I know it seems like a long way off, but ball pythons live for 20+ years. If you go ahead and get him now, you will be forced to either get an apartment (I'm sure it is pretty expensive in Sweden) or get rid of the snake.

Again, don't know how it is in Sweden, or your situation, but I'd rather say it than not. I had to wait until I moved out of the dorms this year to get my ball pythons.