Got my learners permit a few months after I turned 15 to go with my drivers education class. Got my "Intermediate" License at 16.
Stupidly, since it expired on my 21st birthday, I got it reissued a couple days early so I wouldnt roll on expired license. So it still says "Intermediate License" and "Age 21 on.." even though its a regular license now that Im over 21.
So... 7 years or so.