I think that being a capable teacher is independent of being a capable pilot. Obviously you need to be a capable pilot to be a good CFI, but just knowing the material doesn't automatically give you the ability to teach it properly.
I've seen the teaching side of things come more easily to some than others. You'll learn a lot about teaching in the process of getting your CFI - but I'll bet the majority of the learning will be done when you're actually out there with students. I see it this way - when I was out getting all my various ratings/certificates, my CFI was adjusting his/her methods to suit my learning style. As a CFI, it'd be my responsibilty to be the one that has to adjust. That adds another layer of complexity that didn't exist as a student.
For some, like 350driver, the transition is pretty much transparent. But others might have to work at it a bit more. Just work hard either way, and you'll be fine regardless of which category you fall into.