Your travel agent told you to rent gear in Colorado????.....pack it up????....drag it all the way down here????

Hmmmmmmm?
Obviously this travel agent has never been to Ambergris Caye.

Diving equipment is safe to rent here....and you shouldn't need that wet suit unless you are prone to getting cold.

I personally just wear a swimsuit and shorts, but a lot of people like a lightweight skin suit.
Nothing heavy is required.....it's the tropics.