"Justice" and "Fair-play"

My opinions on trying/sentencing children as adults in the case of serious offenses and the idea of punishment versus reform/rehabilitation is that its completely justified. I believe that if the child is old enough to commit a crime then he/she should be old enough to face the repercussions. Although, I think it depends on the age of the child and his or hers reasoning for their actions. If they can't fully explain what they did and why they did it then obviously their mentality isn't fully matured and they shouldn't be sentenced or trialed as adults in a case. But if he/she can defend themselves through reasoning, excuses with detailed information then they should be trialed as an adult.