Absolutely! You'll have to go back to school and take the pre-requisites for med school, and that's probably going to take you about 2 years, unless you got some of them out of the way during your undergrad time. (You have to take 2 semesters of general chemistry and 2 of organic chemistry, and they have to be done in order). Once that's done, take the MCAT, and start applying!
I work with a neurosurgeon who used to be a school teacher, and I've met plenty of physicians that started out doing something else.
If you passed your CPA exam by the age of 22, you obviously have the ability to memorize lots of information, which is a skill you'll need in med school.
The CPA training will help you with managing your practice. We could all use a bit of that training, but get none of it in med school.
I'm an anestehsiologist.