The age of majority is the threshold of adulthood as recognized or declared in law. It is the moment when minors cease to be considered such and assume legal control over their persons, actions, and decisions, thus terminating the control and legal responsibilities The word majority here refers to having greater years and being of full age.
The defense of infancy is a form of defense known as an excuse so that defendants falling within the definition of an "infant" are excluded from criminal liability for their actions, if at the relevant time, they had not reached an age . In the United States, the age varies between states, being as low as six years in South Carolina.
Slightly older teens can be tried in adult courts for virtually every other crime. that allow people to think through the likely consequences of an action, War was partly responsible for that, as 18-year-olds went off to fight in.