I had the mental development to be able to read The Lord of the Rings at 11...I'm sure the notion that murder and rape are bad was fully part of my mental makeup at 13!

You had the Cerebral Cortext development sufficient to read LotR and comprehend the language and some of its implications. But that is very different than being able to link the intention of future consequences to your current decisions.

"murder, rape...bad"

Is not sufficient to form criminal mens rea. You have to have the INTENT TO CAUSE THE CONSEQUENCES. And if your brain is unable to make that connection, and without a developed OFC you cannot make that connection.

That's different than in a cerebral context making a prospective analysis of the long term consequences of an arbitrary act.