If you are looking to get certified Florida is a nice place to do it. The first thing you want to do is get your Open Water Certification, depending on where you do it, it cost about $300. After you do that you can decide wether scuba is right for you or not and then go from there to more advanced classes. I work in a dive shop in South Beach, we teach classes and run trips constantly and the reefs off the beach are pretty nice, especially around Ft. Lauderdale plus they are a cheap trip only equipment rental,. If you want to see turtles the place with the best chance of seeing one is the keys. I have had the most encounters on Molasses Reef off Key Largo, Captain's Slates Atlantis Dive Shop runs trips there on almost a weekly basis so if you are going to the keys I would stop and do a dive with him. Good Luck.