To the girl entering college that thinks she has her life planned out:
Don't.
You may be entering college with high expectations and hoping everything will happen a certain way. But the reality is, very few of those things, if any, are going to turn out exactly how you planned.
You may expect to have a certain major, but you may get to college and find that your passion lies else where. You may expect to join certain clubs and organizations, but you may find that these aren't a good fit for you.
The best advice I can give anyone about to enter college is to go in with an open mind. Things may not turn out the way you want them to, but it will be better for you in the end.
You can plan your life all you want, but God is the only one who knows how its actually going to turn out. No matter how much you want something or expect something, He's going to do what He wants to with your life.