Some people would say it is good for teenagers to have their own job because the experience of work will open their eye. Also they can learn how society work. I understand their opinion, however I think juvenile should focus on study. And sometimes part time jobs disturb them to study.
When I was in high school, I also have a part time job. At first, I was excited to earn money and I could buy whatever I want, so I asked my boss that I want to work as possible as I could. Although, after 2 month my school's grade had dropped down. At that time I realized that it is not good idea to have a job. So I quitted the job and concentrate on studying.
For my opinion, the time people can study is limited. When they are young they can absorb a lot of things; new ideas, perspectives and knowledge. But they can have jobs whenever they want. They don't have to rush for working. This is the reason that I believe teenagers should not have their job.