The biggest problem with college is staying on top of the work load. I have found that everything they ask can be done. It's just a matter of putting in the time and effort, and managing your own learning.
Start off with a lighter course load initially to help build your confidence. Make a schedule for studying and stay on top of the work. If you don't understand something, look into tutoring and find ways to figure it out. Do not let yourself fall behind. Tackle all issues early on. The key is being proactive.
If you're worried about your writing, there are often writing centers in major colleges with people who will read and help you edit your work. Remember, you're there to learn. If you were already perfect at everything, then you'd have no reason to be there. You're the student; not the professor.