kristykins, in another thread I saw where you guys like to do some partying. I hear ya!!
But because of that, and a few other reasons, I'm recommending that you get your classroom, book learning and pool sessions out of the way at home before you leave. Then take your Open Water testing in Belize for your certification.
Who wants to study when they are on holidays? Scuba is a safe sport when done properly but don't ever forget that the ocean can be unforgiving. You owe it to yourself to do it right.