Imho, I think you should stay at least a year to try thing stateside. If you go MUA, you still have to do a year of pre-med anyway. If you do pre-med here in the U.S., it is cheaper to take courses at a community college or state university. And you also have time to study for the MCAT and apply for U.S. med schools.
You are probably aware that it is going to be harder to go Carib than U.S. Asides from the diffculties of being away very far from family and studying in a foreigh country, it is usually harder to make it through school there (the attrition rate is high for many reasons, one is that they let in many who do not belong there). Harder to get in residency, you usually have to score higher on Step exams than U.S. students. Many other competitive specialties are usually out of reach for Carib students.
Speaking about Step exams, Step 1 could be changed to P/F instead of being scored like the way it is now (check out Med Student's MD / DO here on SDN, it is a hot topic now). If changed to P/F, it would add another layer of difficulties for Carib students coming back to the U.S. for residency as traditionally they rely only on performance on Step exams to gain residency. This change is still being discussed but the tentative schedule is that the change could be implemented at the end of 2019 and throughout 2020. So it could be soon. Even if you have already decided to go Carib, I think you should wait a bit to see what is going to happen there to plan accordingly.
Speaking about age, I am older than you (40's) so I understand why you want to go Carib. But I think it is more advantage for you to stay in the U.S. to complete your pre-med study, take the MCAT, and try applying U.S. med schools.
Regarding MUA, per my research, there have been changes at MUA recently. (Do a search here, here are posts about MUA on SDN). I never went there so I have no idea what is going there. But I was not impressed much from talking with the admission office.
A lot of people recommend St. George, one of the big 4 (Ross, St. Geroge, AUC, Saba), and they have pre-med track and also have Title IV loan. My impression from talking with them was good, very informative.
I do not have any idea about SJSM. I saw a Youtube channel of a SJSM's grad who is doing residency in surgery. He seems doing well there.
If you have the money and do not care about Title IV loans, check out more schools. My impression with UMHS was excellent talking to their offices and allumni. They have 4 year and 5 year MD programs.
One important thing about Carib schools, of all the schools I talked too, they are very vague about how many rotation spots they have available for 3 year students. When you look at the large numbers of students they are taking in, it is clear that they are going to squeeze out a lot of students to make it fit the numbers of rotation that they have.
In short, it is good for you to stay to finish your pre-med study, take the MCAT, and try applying to U.S. med school first. It only takes about a year like you said but it will save you a lot work and trouble down the road.
PM me if you would like to discuss more or things you do not want to post publicly.
