I have to agree with you there! Why is it that you have to wait until you are 18 to be able to vote and yet (here in Canada as well) be as young as 16 in order to get a license? Why is that? You are right that a 16 year old's mind is definitely not always where it should be especially now if they have cell phones or even friends in the car with them.
Here where I live, there is a graduated driving program. First off, a 16 year old or such beginner is only allowed to drive with a licensed driver, then they have to take another test before they move on, but still...