Go into college knowing that it doesn't really matter how well you do as long as you get the 4 year degree. Companies could care less what your GPA was or how long it took. Getting the degree shows commitment and dedication, and companies want to hire committed and dedicated people. In a lot of traditional companies, you hit a ceiling pretty fast if you don't have a degree. Most management positions at these companies require a degree, regardless of competence or skills.
When I was in college, we'd learn material for 3 months, take the mid-term, then forget everything and move on to the second 3 months of material, then the final, then forget everything in time for the next semester. This used to concern me back then, leaving me to wonder how I would apply anything I "learned" in these courses to my future job. The trick is, pretty much nothing you learn in college will apply in your future job, so don't worry too much about it, just learn the material long enough to pass the course.