Describe, if you would, the transformation the brain undergoes on the day one turns 18. Is there really a difference in maturity between someone who is 18 minus one week versus someone who is 18 plus one week?
Or are you simply opposed to the death penalty, and will take anything you can get towards its abolishment?
The law can only deal with the quantifiable. The law is wholly inadequate to deal with maturity levels. You may be ready to take on the responsibility to drive at 15 1/2, but it doesn't matter, you can't get a license until you turn 16. No matter how abitrary, the law only works well with hard and fast cut-offs.