What happened to me is this:
I took all advanced, college credit math courses through high school, getting repeatedly told the line of "You won't regret this, it transfers in to university so you won't have to take calculus and can graduate faster!"
But what happens is the university sets up six calculus courses for example, lets say courses Calculus 101, Calculus 102, Calculus 103, and then a second set of calculus courses numbered Calculus 201, Calculus 202, and Calculus 203. Your degree will list the 200 course track as the required courses, but the transfer credits only count for the 100 track. There is practically zero difference between the courses, and only the 200 course track is offered at the university. You basically waste your time/money in high school/community college, but can't do anything about it because technically you did get transfer credit for Calculus 101-103, its just its useless in the goal of graduating with your degree though.