What should be the age at which a child can be responsible for a crime?

My opinion is 12. It would never fly, in 'this' society, but that's the age I think a child should be punished as an adult for crimes.

Age of reason is 7 years old. By that age, kids understand right vs wrong, and can understand if they are causing harm to someone else or an animal.

When they're old enough to decide to have an abortion without parental permission.

As soon as they are aware that it is a crime.