Scuba Snorkelling

I haven’t been scuba diving in a year now and I’m going crazy. Where are some good spots to scuba dive around Florida. I’ve already been to vortex. I want a place where the visibilty is good and is any where from 15 to 85ft deep.

Oh and how old do you have to be to get certified in nitrox. I can’t remember if it’s 18 or 16.