The government should not set the driving age and should not own the roads
You probably live in the middle of suburbia. A place made up of two groups of people – those with a driver’s license and those without one. And though it is blatantly obvious that everyone should be allowed to have a driver’s license in suburbia, the government is aggressively trying to make the driving age equal to the drinking age.
Since the government owns the roads, the politicians can decide who is allowed to use them. Politicians also control the sidewalks, which is why they can outlaw loitering.
When you turn 18, vote for Libertarian politicians who will sell off all the roads and sidewalks to private businesses. Since private road owners want to make money, they would let all COMPETENT drivers, regardless of their age, drive on their roads. If a 7 year old can pass the driving test, then she gets to drive.
Would it be anarchy? No, because everyone still has to pass a test. But this test would not be given by the government.