I’m amused that you were turned off by writing for your own financial gain; is it that commonly negative opinion of marketing and advertising? My thought has always been that I would never market a product I didn’t stand behind or write anything about it that wasn’t true. I guess there are marketers who are less than scrupulous, but we’re a surprisingly decent group (but then maybe it’s because I have focused on decent products so that’s all I’ve met!).
I’m also intrigued by you and others on Medium who weren’t “born” with the writing bug. What are your other creative outlets?
Anyway, you don’t have to jump head first into a writing program; you could just take a class or two and see what you think (two is better, so that if one isn’t ideal you can separate concept from implementation). I do recommend going to a better university if you can, because the caliber of the students around you will make all the difference in your experience.