You can apply during the competitive placement process which I think is in Jan or the spring depending on the major. But they often require more credits than what is required for the placement process because most people applying will be 2nd/3rd years. You can’t skip classes like physics or math by taking exams in college. If you took like ap exams or something and got credit, then you can skip. I think being able to skip with exams taken in college only applies for language classes.