It's been a long time since I made that transition. :) but I believe that in college, you are likely to have a lot more autonomy and independence. That means you'll have to make more decisions on your own, and use good judgment as often as you can.
You'll meet lots of new people, which is fun. You'll have more control over the classes you take and subjects you study, your schedule, your extracurricular activities. Sometimes all the choices can seem overwhelming, but it's a great time to try new things.
I suggest you keep an open mind. And try to not over-schedule yourself. Leave time for studying on your own (homework assignments may be less rigid but more time-consuming) or with friends, and don't forget to eat/sleep/take care of yourself. Trust your instincts, but don't hesitate to ask others for advice (about professors, or activities, or places to eat, or other people).
Hope this helps! It's an exciting time and I'm sure you'll do great.