I noticed a bunch of your threads here recently, all pretty much about the same thing...
I think you should talk to an parents, student councilor or close adult about this. No one here knows your situation and how practical your dreams are. An adult who knows what your financial limitations are, knows your talent, and knows your general plan for the future will be able to give you much better advice. And discuss it with someone other than your boyfriend... if he's close to your age, he doesn't have the kind of life experience needed to be able to help you make the best decision.
Now, keeping in mind I don't know you, my only advice would be that there are tons and tons of girls that grew up riding, and there's only a small percentage that end up teaching/making money off horses. And an even smaller percentage of them are truly qualified to teach others to ride. Based just on cold hard statistics, it's unlikely you will be able to make a living teaching others to ride. You will need another source of income.
Keep your major in child education. You will need it.