The best way to make a small fortune in the horse world is to start with a large one.
People say that if you have a job you love, you will never work a day in your life. This is true, to a point. When the work day ends, and you don't have money to do anything fun, or your work day never truly ends - will you really feel the same way? Barn managers don't make very much money. A lot of people say that's okay, because they're not into material things. However, all things that are necessary require money. You may very well have a job you love, but you won't make much money. Cars break. People break - what happens if you fall? Who will run the farm and train the horses? What happens if you get hurt and can't ride anymore? Who will run the farm and train the horses? What would you do for income?
Stay in college, get the degree. You can always learn how to be a trainer and do that on the side if you really want. You can also save up and one day buy a facility if that's what you really want to do and hire excellent staff so that you're not tied to the barn 24/7.
Biochem will pay leaps and bounds more than any horse job. Yes you'll be in a lab all day, but you will be able to afford better for yourself and your horse(s) off of that paycheck than you ever could in a barn.
* I'm often reading and posting from mobile and Siri loves to make a mockery of the English language.