The CDC and U.S. State Department has approximately 80 percent of the destinations around the world at Level 4 -- Do not Travel. With a percentage of countries/destinations this high, the message is simple that they just don't want people traveling at this time, even though many of these countries have stark differences in the number of active COVID cases and vaccination rates. But, if you are fully vaccinated and take simple precautionary measures before, during and after your trip you should be just fine. I don't believe the number of active cases being reported on French St. Martin are accurate, and need to be updated. But it's wise to assume that many of those around you on St. Martin may be unvaccinated, so I would suggest maintaining some separation between you and others when indoors, and wearing your mask indoors. I suppose the biggest concern would be testing positive before heading back to the states and not being permitted to board your return flight. But, I do think that's unlikely and I would not change my plans at this time.