I can relate to all of you. I am 22 (almost 23) and was diagnosed when I was 9. I would definitely tell your professors and close friends, at the least! I don't broadcast my diabetes to everyone, but I am not shy about it either. I remember when I was first diagnosed, though, I was apprehensive to tell people I had diabetes. A lot of it was probably because I didn't completely understand what that meant, besides the fact that I had to poke my finger, count my carbs, and take shots. I got a lot more comfortable as I got older. You might even meet other students who have type 1 DM too! Now, if I need to take a shot, i just whip it out and inject wherever I am...literally!
I was taking a big exam last week and felt a low blood sugar. Fortunately, that class size was small, and I was able to check my BG at the teacher's desk and took a handful of glucose tabs. Some professors, especially at big universities, may not be understanding initially if they don't already know that you are type 1 diabetic. I take shots now, but in the past when I had a pump I just had to remember to put it on vibrate before exams!!
If you're away from your dorm/apt/home, remember to always have glucose tabs or jolly ranchers (or whatever you like) on you. I personally don't tend to notice my low BG's until they're really low, so it's important to keep quick fixes on you. And watch your blood sugar on test days. That time I mentioned above, it was extremely difficult for me to take my exam since it took some time for me to re-orient.
Hope any of that helps!! And I sure appreciate reading all of your stories. Makes me remember that I'm not the only one!