Does she dive down, several feet below the surface, and slowly tour around or linger awhile, "correctly" weighted for this? Or does she remain on the surface peering down into the water? I'm thinking that the more comfortable she is doing the former, the easier will be her introduction to scuba.... she _LOVES_ snorkeling, is very comfortable in the water ...
In the few weeks before you two leave for the Caribbean, will you two be able to get in some pool time, wearing mask, fins, snorkel, and weight belt, and the thin wetsuit you'll be wearing in the Caribbean? I'm thinking that surface swimming (snorkeling) in this snorkeling gear will prepare her legs, and snorkeling in the deep end (diving to the bottom to gently kick around there) will prepare her to be more relaxed underwater and allow her to practice her snorkel clearing and mask clearing. Doesn't take much: A couple of pool sessions a week, each of the next few weeks almost certainly will be enough.
rx7diver