You could definitely have a house built between now and Christmas. Honestly a wooden house can be built within a month. A concrete house takes longer but if your funding is timed correctly and your builder is professional enough to be able to plan the shipments in a timely fashion a 6 month build is well within the realms of possibility.
Amanda you have everyone who has ever built a house on Ambergris Caye rolling in the aisles.
Lets see just run over and get a permit in the morning then buy the materials in the afternoon then get the boys to throw it all together. yep not difficult at all.