Fortunately people tend to have matured a lot by the time they get to college. A few will still be acting like jouvies but for the most part they're all trying to do the adult thing and are getting more considerate and losing their tendency to make fun of and belittle people, so the atmosphere will be a lot better than in high school. And if you get caught, they're a lot more likely to be discrete about it.
A lot of colleges require freshmen to live in dorms with a roommate not of your choosing, "to get used to college life". There will be some privacy, but it will be marginal and not totally reliable. A lot of it will depend on the blind luck of who you get for a roommate.
I'd suggest more than one diaper per day. I wear 24/7 and I go through around 3/day. One strictly for overnight, one for day at work, and one for evening. Many days only my overnight diaper gets wet. Of course if you plan to wet during the day that will increase the padding you go through. You're going to have to restock a few times a semester unless you show up with cases. (unlikely) So make sure you have a plan for restocking as needed. If you only intend to wear during the day and not wet, consider going with 2 diapers/day, because wearing them out and around wears them out fast and dry diapers get lumpy and can tear if you wear them too long. You could also just wear one during the schooling hours and spend your evenings and nights without but that seems to me like a wasted opportunity.
My current recommendation for wearing to work or school is Tykables Little Builders. They're good quality, comfortable, can take a few wettings, aren't too thick for wearing under clothes (not too thick to show nor to get crushing the jewels) and cost is fair for frequent wear. For evening you might look for something slightly thicker but still priced reasonably. Maybe ABU Preschool? (available in clothlike and plastic) Go wild for overnight if you plan to wet
The other thing to consider is disposal. Colorful diapers really show through cheap white trash bags. Dry diapers are MUCH easier to deal with than wet ones. Tykables aren't all white, but preschool is mostly white and there are a number of (particularly the thicker) diapers that are all-white that will make disposal a little more stealthy.
You might be able to confide with your roommate that you wear diapers, give him some reason like you sometime dribble so wear just to keep spots off your pants. Things like "didja know my roommate wears diapers?" makes good table talk at the bar at 1am so it's hard to say if they will keep that a secret or not, but talking with them about it ahead of time makes it less likely that you'll get discovered without knowing and he'll let it slip later.