Family.
I agree with youngtrep, though for slightly different reasons.
Here is my take on it. If you are smart, which you seem to be, school won't take up 100% of your time. I got mostly A's, and I studied MAYBE 3 hours a week, MAX. I didn't know about business then, so I generally wasted my time playing video games and chilling with friends. But you have an advantage. You know about business, and how you want to do your own thing.
Look at college as a relatively easy way to live for 3.5-4 years without having to worry about food, insurance, housing, or pretty much anything. If you don't go to school you need to make money just to survive, which takes time away from your other stuff and also stresses you out.
I say stay in school, ride the system, and slam on your business for 4 years. If it takes off and you are making 100k profit per year before you graduate, then feel free to drop out!