First make sure you really want to do this. The burnout rate for physicians is considerable. Thats why med school committees want to see shadowing or other experience in dealing with patients.
Second, how do you feel about rote memorization? Lots of the first two years of med school involves memorizing. You have to be good at it. Some people don’t like it.
Finally, have you considered delaying your graduation until you fulfill premed requirements? This would enable you to get a committee letter from your undergrad institution. Often better than getting letters from a post-bac or DIY program.
The Caribbean MD programs are notorious for being money pits - highly suggest to avoid at all costs.