+1 Having done both, trading is much more about study and practice, and then you vs the market. If you like research, from college or whenever, you'll love trading. Being an entrepreneur does involve solid research about your business area and preparation, but also involves many other areas. You've got to deal with employees, customers, laws, cities, payroll, rent, a bad economy, competition, independent contractors, etc. In my opinion, an entrepreneur has to keep track of many more moving parts in order to be successful. Both are very risky; there are some business areas that are safer than trading, but they don't have the same upside. Businesses that have big upsides have the requisite risk.
In some senses, I've always felt a top discretionary trader has much in common also with a top-ranking professional sports person. I wouldn't say the same is true for an entrepreneur, though.
Technically it is a business just like a lawyer who opens up their own practice. Entreprenuers get people and ideas together to create an entity that serves a need and thus creates wealth. Entreprenuer is the guy who assembles all the players to make a baseball team. The trader is playing tennis. Personally I think the risk/rewards are better in proper business than in trading. (Which is why I am moving away from trading). You can lose your shirt in both, but in proper business, your customers are generally okay with "paying away edge" as they need you to do something for them.