Imagine you made a terrible mistake when you were very young - a mistake for which you may have to pay with a substantial number of years of your liberty, and a chunk of your employment prospects and - as a result - your future earnings, as well as living with the guilt for, what 80 years?
Imagine that mistake involved that feeling of invincibility that youth brings, and that sensation that seems limited to the young of imagining everyone is as sharp, switched on and alert as you are. Remember how, when you were 18, you couldn't comprehend how middle-aged people were so slow witted, and why their reaction times were so slow?
Now imagine you're in court on trial. There are certain facts you cannot reasonably deny because there is hard evidence and witness evidence.
Assuming you don't want to go to court and say "It was all my fault - have mercy on me" what would you say any different?