There are a lot of things I still would like to do in this life, and a lot of things I wish I'd done while I was still in college. Mostly, I wish I would have taken more time to explore other areas of academia--science, for instance, and outdoor recreation. There's still plenty I can do to explore these things, but I know I would have benefited from exposing myself to them more while in college, where there are endless resources for any kind of academic and nonacademic pursuit a student wishes to investigate.
Whether you are in college already or preparing to attend, I would encourage you to think carefully about both your major and the things you pursue while in college. If being an entrepreneur is your ultimate goal, you would do well to expose yourself to as many different activities--both academic and extracurricular--as possible.
The reason I recommend this strategy is that entrepreneurship requires such a diverse range of skills that it can only help for you to get involved with a diverse range of activities. When you are an entrepreneur, you're a salesperson, marketing expert, accountant, artist, writer, financial expert, tech guru and manager all at once. Of course you will be more of one thing than another based on the type of business you want to start, but essentially it helps to have skills in many different areas.
So while you are in college, remember that your major is not as important as the things you get out of your total college experience. Get involved with campus clubs, offer to write an article for the school newspaper, learn some computer skills, get a job in the campus bookstore to learn about managing money and keeping records, take an art class--do whatever you can to get a taste of all different disciplines. At the same time, be sure to specialize in something--you don't want to be a jack of all trades and master of none.
When you start a business, you'll find yourself wearing different hats day in and day out, depending on the circumstances. By taking the time while you're in college to expand your horizons--yes, your mother was right about that--you will know in an instant which hat is appropriate for which situation. And you'll wear that hat with confidence.