Answer:
It depends where you are.
Where are you? i don't know?????????
In most jurisdictions, getting a motorcycle license requires that you reach the same age as you must be to drive a car. After all, the responsibilities are basically the same.
You need to know the rules of the road; you put your own life and the lives of passengers and other drivers in your hands when you head out for a drive, so you'd better know what you're doing......and be mature about your driving behavior.
Check with your local licensing office. They're usually in the phone book under Motor License Office or in the government listings area under Motor Vehicles.
Good luck.