Your roommate might be your new best friend or your new biggest enemy; there's no way to predict this in advance. If the two of you do not end up liking each other, don't worry. Be polite to her and try to make the best of the situation. You might even be able to switch roommates, if you talk to your resident adviser.
Many professors do not make attendance mandatory, but this does not mean that you should make your presence optional. When you go to class, you have the opportunity to listen to the professor's lectures, ask questions, learn assignment due dates and make friends with your classmates. Missing out on these things will negatively impact your grade.
Colleges have endless amounts of extracurricular activities available for students to participate in. Whether you want to join an intramural basketball team, write for the school newspaper or become a campus tour guide, there's an activity for everyone. Joining a club will give you a chance to do something you enjoy, while making friends with people that share your interests.
College dining halls serve a wide variety of food, including many not-so-healthy options. Your parents will not be there to keep you from eating pizza and fries. Make sure to keep your diet balanced by mixing healthy food, such as salads, fruits and vegetables, into your daily diet. The "freshman fifteen" is not a myth, so do your best to keep your diet under control.