Welcome Momofmd to cruise chat and congrats on booking your cruise. There are plenty of cruisers that will be happy to supply you with some suggestions for your ports. Labadee is RCI's private island area and a beach day. The stop provides lots of water sports and a new zip line that may be of interest to your teens. A climb up the famed Dunns River Falls may be of interest to them as well and snorkel tours would be available there as well as on Cozumel. Also available on Cozumel are various ruins if they would be into this sort of tour.
Several great beaches are within easy reach as well...Enjoy that great new RCI ship. Speaking of tours, just attempting to take in all that it has to offer could be a full time tour in of itself.