Interesting enough, the idea of 21 being the age of accountability is based on the medieval concept that, assuming you were an apprentice at 7, journeyman at 14, by 21 you had been an adult for 7 years and were a master craftsman, capable of signing contracts and training your own apprentices.
Well put. Many do not realize this. We have a seventeen year old daughter who is caring for an elderly lady across the street. She does everything from cooking to shopping to bathing for her. This lady has her own children and grand children who would rather pay our daughter than do it on their own.