Florida law is very confusing regarding this issue. Florida law makes a distinction between mopeds and motorized bicycles. One interpretation of Florida law requires that you need a driver’s license to ride a moped, but not a motorized bicycle. A bicycle with a motor is still a bicycle. It does not become a moped. For the other interpretation, see BEWARE section below:
§ 322.01(27), Florida statutes says:
“Motor vehicle” means any vehicle which is self-propelled, including a “moped,” but not any vehicle moved solely by human power, motorized wheelchairs or motorized bicycles. (Emphasis added.) 
The jury instruction for No Valid Driver’s License (28.9) says: “A ‘motor vehicle’ means any vehicle which is self-propelled, including a ‘moped,’ but not any vehicle moved solely by human power, motorized wheelchair or motorized bicycle.” (You don’t get a jury trial for a No Valid Driver’s License charge. But the statute book still lists the “jury instruction.” It shows what the State has to prove in court.)
The jury instructions for Driving with a License Suspended or Revoked (DWLSR) and DWLSR habitual have identical definitions of “motor vehicle.”
BEWARE
The above interpretation may all be wrong based on 316.003(2) which defines “bicycle.” That definition says mentions that a motorized bicycle has an electric motor.
The 50cc test
You’ll often hear of the 50cc test, that if the motor is less than 50cc, you don’t need a driver’s license. This is NOT the law in Florida. For example, you could have a moped with a 49cc engine. You would need a driver’s license to ride the moped, even though the engine size is less the 50cc. Florida law focuses on the type of vehicle. So, don’t rely on the 50cc test.
“You don’t need a motorcycle license.”
Here’s another trap. Many people who get cited or arrested for driving a scooter without a driver’s license have said to me, “When I bought it, they told me I don’t need a license because it’s less than 50cc.” In Florida, you don’t need a motorcycle license or endorsement to ride the scooter, but you do need a driver’s license.