hi carlyn, welcome to CruiseReviews! Congratulations on your up-coming cruise! RCI has a great program for teens, they also have plenty for them to do on board. There's the rock wall, the pools, basketball/volleyball courts, and video games.
The southern Caribbean has some of my favorite ports. Not sure what y'all enjoy, so I'll just mention some of the places I enjoy in your ports. St. Thomas, we usually take the ferry over to St. Johns and go to Trunk Bay. Trunk Bay is one of the top 10 beaches in the world. There is a self-guided snorkel trail about 50 yards from shore and they have all the ammenities you need, including lockers. If you want to stay on St. Thomas, Megan's Bay and Coki Beach are two of my favorites. There's also great shopping in St. Thomas, especially jewelry and liquor. St. Kitts, I enjoyed the visit to the fort and the Batik factory. The snorkeling there is not that good, but the island is very pretty. Aruba is a very flat island, so not much sight-seeing. However, great beaches and clubs. The last time we were there, we took a cab to Palm Beach. It was about a 20 minute ride, they had a pier with a restaurant/bar, chairs and umbrellas for rent, water toys, showers, restrooms. It was a great way to spend the day. Curacao has some decent snorkeling, but the main attractions there are the colorful houses, shopping, and the Curacao factory. I've done an island tour through the ship, a couple of snorkeling trips through the ship, and just taken the ferry across to do shopping. There are quite a few restaurants/bars right where you dock, with a beautiful view and friendly locals. Oddly enough, I've never gone to a beach in Curacao, so I'm not sure if there are some great ones or not.
I think your daughter will be so busy, she won't have time to freak out. I really believe her main problem will be fitting everything in
Please let us know what your interests are and we'll do our best to fill you in on excursions. Just be warned, cruising is addictive!!