April 26, 2020
This question isn't dumb at all, and even “The Dean" remembers worrying about the same thing when I was your age, nearly a half century ago (or maybe we're both dumb?) 😉
College schedules typically allow 10 minutes travel time between classes. In other words, your 9 a.m. class would get out at 9:50, so that would provide the 10 minutes that you think you need to reach the next class on time. Professors at the really large schools—especially those campuses that rely on a network of shuttle buses—are often accustomed to latecomers. So if you're in a situation where you feel that you need MORE than 10 minutes to get from one class to the next, just email the prof of the second class before registering to ask how strict he or she will be about starting right on time. But I bet that it's only on the very largest campuses that 10 minutes may not suffice. Otherwise you'll be fine, especially if you have a bike … and as long as you don't insist on a Starbucks stop on the way to your second class!