No question that it is comparing hamburger to fillet, but you won't regret having made that decision. Learning to dive in that lake will help prepare you for future dives in ways that you won't realize, until you encounter low viz and/or cooler temps.
Since you have the time, take the course that stretches the learning out over a few weeks rather than a two day course. It has been proven that more is retained over the longer course. Then, a few days or a week before you come to Belize, see if you can get a refresher in the pool to practice your skills. If you can't fit that in, then do a skills refresher dive under supervision, as your first dive in Belize.
Best to you, in all your adventures.
AmbergrisCaye.com 
