I have often thought that being elderly, even if quite fit, does increase the odds of a medical emergency while traveling. Only the young dismiss this. If you have any concerns about getting "emergency" care/treatment beyond the capabilities of the BVI, then perhaps some travel insurance would be worth thinking about - it's not that expensive. I am certainly not paranoid about this, but there are plenty of stories where someone has needed to get evac'd to Puerto Rico or even Florida to get a needed level of attention.
Perhaps someone here can comment on the quality of medical services on STT, which I assume is the closest major facility.