Before you come to Mac as a freshman, you have to sign up for courses over the summer. When I looked over the course listings in June, I was a little bit intimidated by the wide variety of course offerings. There were even a few course descriptions that were fairly dense and confusing. I got nervous, thinking it would be hard to branch out into academic areas I had little to no experience in. In the end I signed up for several courses that I was more familiar with, like calculus and the major sciences, but I also signed up for courses in departments that interested me, which I had no prior experience in, such as economics, psychology, and geology.
Luckily, I ended up being placed in Principles of Economics and Dynamic Earth and Global Change (intro to Geology, essentially). However, I was also placed in two classes I hadn't initially signed up for: Sounds of Language, a Linguistics course, and Modern Astronomy. As it turns out, I didn't take any of these subjects in high school, and with the exception of Geology, I really didn't know what any of them were actually like.
But that didn't matter. Turns out I had nothing to worry about. When the classes started, I didn't feel like I was lagging behind or anything. The classes were truly introductory classes. They started from the very beginning. Having some prior general knowledge was certainly helpful, (go 6th Grade Earth science!) but by no means necessary.
As prospective college students, I strongly encourage you to explore new areas of study, perhaps beyond the mandatory distribution requirements, even if you are already set on a major/career course (pre-Med etc). After all, that's the whole point of a liberal arts education, which I know you are interested in if you're looking at Mac. Macalester eased me into all of my classes, and I am absolutely enjoying all of them. But more on that later...