I was about to give my reccomendation, then saw the comment that brought up the issue of your age and therefore potential change if living arrangements in the next few years.
In light of that I suggest you stay small. While larger snakes are (in my opinion) great and with experience and work just as easy to keep and handle as small ones, their housing can be quite daunting.
My ORIGINAL suggestion was for a Central American Boa. That was my first snake and I can’t reccomend them highly enough! Essentially the same husbandry requirements as a BP in terms of climate, but they are more active and inquisitive, they are less prone to stress and stress related ailments, they always always eat but only need to eat half as often. Within the Central American locales there are some true dwarfs (island and mountain localities) but most CAs are generally smaller than their southern cousins. A male will tend to be smaller still. Mine is a male, 4 and 1/2 years old and about 4 and a half feet long and about as think as a chubby corn snake, but with that classic boa loaf shape and as muscular as a steel cable. Very satisfying to handle, feels much stronger and more substantial than his size suggests. Puppy dog tame (see below)
However, he’s in a 4x2x18”, and that is a big heavy box to move to dorms, apartments, and the like.

My alternative reccomendation is a rosy boa - I don’t have one so I can’t rant and rave like I did above, lol. But I’ve been thinking about getting my son one so I’ve done some research and the long and short of it (no pun intended) is that they are a smaller snake that doesn’t climb so every dimension of the housing can be smaller, but the personality is supposed to be just as big.

One more thing: BEWARE, this may be your first snake, but it won’t be your last, they are addictive! 🤣