What are the age requirements for a person to be competent?

I've known 12-years who are more competent in some things than many adults. People who are 16 are allowed to drive; 18-year-olds can vote; 21-year-olds have full legal status. A Time magazine article pointed out a few years ago that most people's brains don't fully mature until they're about 25.

Thank you for using the Jiskha Homework Help Forum. Here is a most interesting site on competency during various ages:

http://www.au.af.mil/au/awc/awcgate/army/erickson_stages.htm