Do you need a license for a quad?

Technically, no - since it's an off road vehicle. However guidelines for riders stipulate that the rider must be 16 years of age and older, so it's somewhat understood that you would be of age to have a drivers permit.

As long as you ride your ATV, ATC, UTV on your property - that's your business and liability. The minute you cross onto public land, or cross a public roadway, you must be in possession of a valid drivers permit.