Hello Dorarichie - welcome to the forum!
Although Belize is a small country geographically, it varies quite considerably from region to region. Where to consider is dependent upon what you are looking for. There is a lot of information available on this forum, and from other sources as well, regarding potential areas in Belize. I will give you a short synopsis:
The Cayes - part of the second largest, but probably the greatest, barrier reef in the world, are unrivaled for diving, snorkeling, fishing, relaxing.
Orange Walk/Corozal - close to Mexico and easy to get there, less rain than in other areas of Belize, mostly flat to slightly hilly terrain, a lot of agriculture (cane sugar), fishing villages, adjoins Corozal/Chetumal Bay. Good for access to Caribbean sea.
Belize/Belize City - urban, business, commercial and government offices, port of Belize. High crime, little in the way of redeeming qualities. Some of the areas outside the city are comparable to most of the rest of Belize.
Stann Creek - Agriculture, fishing, small villages, mostly rural, but also includes Dangriga and Hopkins on the inland coast. Rolling hills, foothills and some of the Maya mountains in this region, it includes 1/2 of the Hummingbird Highway. Lots of citrus farms. Gets a lot of rain, almost as much as the Toledo area
Cayo - Has probably the largest population, and probably the largest number of ex-pats. It includes several cities, including San Ignacio/Santa Elena and Belmopan, the capital. Also includes the area of Pine Forest Mountain Reserve. Rolling terrain, lots of rivers, lots of agriculture. Spanish Lookout is also located in Cayo, the largest Mennonite community in Belize- looks like Iowa. Less rain here than in Stann Creek or Toledo.
Toledo - the most rain in the country here in southern Belize. Includes Punta Gorda, the largest city in the south. Primarily agriculture and fishing on the coastal areas here. A lot of bananas and corn. Flat to hilly terrain, from the coast to the southern Maya mountains, a wide variety of landscape and geography. The majority of the Mayan population lives in Toledo, and there are some specific restrictions for non-Mayans in some areas here.The least populated of all the areas in Belize.
Take your time and visit as many areas as you can.
Hope you enjoy your trip!