So, basically you say children should be able to work in 8th grade? I think at this age they should be focusing on education and not money. They are still very young and inexperienced in the work field, and there wouldn't be much they would be able to do. At this age, they should focus on school.
First off, people who are 16 usually get entry level jobs anyway. People who are 14 are even less experienced. No one would hire you because not only were you young but also inexperienced in the work field. My point is, even if 14 year olds could get a job, no one would really want to hire them. Jobs may also take their focus off school and even cause them to drop out or think about dropping out later on. This is evident in teens in high schools.