I thought of the Keys also for similar reasons. Lots of shallow dives on reefs and a few shallow wrecks. Save the deep wall locations like Cayman or Turks/Caicos for when you have more experience. Also they're pricey. Don't discount shallow dives - the light is better and so is the coral.
A little more exotic might be the USVI's/BVI's On St Thomas = St Thomas Diving Club has a reputation for working with newer divers and most of the dive sites they visit are shallower. One of the best is Cow/Calf Rocks it's all of 40-50' deep, There's even some shallow wrecks you can tour.
We dove the Cays in that area - 50' put you on the bottom. They're located at Bolongo Bay resort.
Or take the ferry over to Virgin Gorda and dive with DiveBVI - they exemplify valet diving, have excellent rental gear and will provide a DM for you as needed. A teen/dad on our boat got their own all week. Plus all their dives are shallow - even the famous Rhone wreck - all of it above 70'. They will escort you through the bow also since it's open on the sides it can be done by anyone. One member of our group did it on her 10th dive. Most dives we did with them were under 60' except for a couple deep wrecks. And we're a group of experienced divers - they didn't have any sites deeper to take us. Really hilly, often windy there's a lot of yachts. Also better restaurants than you'd expect for a an island with 10K residents - lots of villas up the hills draw money. And safe, our villa mgr. could not provide door keys when asked, they'd never needed them.
I could make a case for Barefoot Divers/Cay on Roatan also. They rent Scubapro gear - my buddy commented their rentals were better than he owned. Real valet diving, small boats, small groups - several members here have posted that they were the only divers that day - some of the resort guests don't dive - our experience also - my group was their business that morning.
Maybe Curacao also. It's really low current diving for the most part. Ocean Encounters has shops at several resorts and they are very safety conscious Curacao is famous for shore diving - almost every dive is a walk in from the beach. Most of the dives we did (25) were in the 60' range - it seemed the most animals lived there. One of their signature dives is the Tugboat - it's 17' deep. Also the Dive Bus for escorted shore dives to get you started - pick up in town, go to a good dive site and do two dives with their DM. Later try some of the same dives on your own. Lastly for $200 pp you can dive with the Dolphins there. The dive takes place on a 40' deep reef and you get about an hour with them. Curacao also has nightlife, good restaurants, lots of natural things like hiking to do. Most people speak English which is good since there;s a lack of street signs once you leave town.
The Scubaboard Surge is there this week. They stay at the Sunscape AI resort in town. Ocean Encounters has a shop there and there's an easy beach dive out front.
Check the rebuilding efforts if you pick the VI's they were trashed in a recent hurricane. I've read St. John is still rebuilding as of last August. As are some resorts on Virgin Gorda
