Hi Mike,
Welcome - and don't worry, you posted in the right section!
My (probably bias) recommendation would be to go for a PADI course, they are the most internationally recognised diving qualification. So, if you get PADI certified you shouldn't ever encounter problems diving elsewhere.
Your first qualficiation would be Open Water Diver, which consists of a theory and practical sessions.
You can actually do the
theory online now, so you don't have to do what I did and spend your holiday nights sitting up reading a handbook, haha.
I haven't personally dived in Florida, so I can't give you a recommendation. My advice would be just look for a 5 star PADI centre.
I'm sure someone here can give you a recommendation for Florida - if you want to get really nitty gritty, you can check if instructors are up to date and still certified with PADI.