It's hard transitioning between them because of the different expectations between the two. In school, most people like that their teachers are on top of them when it comes to their work, and how much they're involved with their learning. While universities let the students to all of the work. University students' work and learning is all up to them. They get to decide to do their work, and skip classes without any lectures; but they are left with the consequences of their learning.
The biggest change when it comes to regular school and universities is the amount of control you have. In school, everything is limited and already controlled for you. Your schedules, classes, are all managed already. On the other hand, university let's the student choose the classes they want to learn, and what time classes start. Overall, schools set students up for the future, and universities let students explore their independence.
(it said a short essay, so do what u will if it's too long for ur liking!)