You'll have to check with regards to being licensed in the State of Florida. Not sure if your state requires it.
Here in NY one becomes licensed with either a background in LE, or by 'working' under a licensed PI for a minimum of 3 years.
Be careful of starting out on your own, before you check those license requirements.
Has its ups and down - matrimonials suck in my opinion - either you catch someone or even if you don't, its hard to 'please' the client. Might want to look into gearing a business towards witness statements, insurance claims, criminal defense, auto accident scene reconstruction, workers comp claims, skip tracing, bounty hunting.
Downside, its not like Magnum PI - No hot chicks, no helicopters, or fast cars. If you enjoy sitting in a car for 8 hours or more in 100+ degree heat, tinted windows sweating your balls off fighting off a migrane you'll love it
Feels good to nab someone, or nail'em in a statement you've obtained. Pay is sometimes hard to get even from lawyers and insurance companies.
Try it, you just might like it though - just be sure to check out those requirements in your state.