Peter and I did OW dives 1 and 2 with a student yesterday. He had elected to do the dry suit option, because an attempt in a wetsuit resulted in him shivering within five minutes. He did superbly! He had a few buoyancy oopses, but caught them all and reestablished stability.
If somebody who's never dived before can do that, so can you.
Given what you've said about your cold tolerance, I'd highly recommend a Fusion Sport dry suit, with or without a set of X-shorts. The Fusion Sport is so light and easy to pack, you can take it anywhere. Get the user-replaceable seal system, and you've fixed the one downside of travel with a dry suit, which is the problem of getting seals replaced if you damage one in a place where nobody else dives dry. The Sport weighs no more than a good 5 mil wetsuit and packs as easily. By buying a laminate-type suit, you have the option of diving very cold water, with thick undergarments, or fairly warm water, with thinner ones, and you will LOVE getting back on the Caribbean boat and not shivering!
If somebody who's never dived before can do that, so can you.
Given what you've said about your cold tolerance, I'd highly recommend a Fusion Sport dry suit, with or without a set of X-shorts. The Fusion Sport is so light and easy to pack, you can take it anywhere. Get the user-replaceable seal system, and you've fixed the one downside of travel with a dry suit, which is the problem of getting seals replaced if you damage one in a place where nobody else dives dry. The Sport weighs no more than a good 5 mil wetsuit and packs as easily. By buying a laminate-type suit, you have the option of diving very cold water, with thick undergarments, or fairly warm water, with thinner ones, and you will LOVE getting back on the Caribbean boat and not shivering!