I'm no expert on the Belize education system, but the basics are that it is patterned after the English system (forms, A-levels, O-levels etc.) with some recent changes reflecting Caribbean and U.S. influences. The Catholic Church runs a majority of the schools but with funding by the government. Some schools, especially secondary schools, are run directly by the government. There are some private schools as well.
What people tell me is that the quality of education varies, being highest in the "elite" schools in Belize City and perhaps lowest in the some of the remote southern villages. The schools in many areas lack a lot of things -- equipment, books, training materials. Teachers don't make much -- US$5000 a year maybe.
Education is compulsory at the primary levels but a lot of kids drop out after that due to the cost of books and so forth, which generally are not provided by the government.
The newly reorganized university system, now called the University of Belize, has three campuses. Many top students go to the U.S., U.K., Jamaica, Guatemala or Cuba for post-secondary and professional schooling.
Given the resources of Belize, I think educational quality is pretty high. The best students are certainly competitive with those in the U.S. But as in the U.S., there's a great variation in quality of schools.