This is fine. We have many floatation devices. Our crew members have a lot of experience with people who are aquatically challenged.
Of course, the more practice you can do in a local pool before coming — from floating with your face in the water, holding your breath… or floating face down with snorkel and mask on… to practising swimming — the less time you will need to become familiar with those things in Bimini, and the sooner you can direct your focus towards the dolphins while in the water.