Until you are 14, you have limited choices for “real” jobs. Agricultural work is one of them. If you live in a rural or semi-rural area, you might have some farms in the area that are in need of some part-time help. In many places, individuals under 14 years of age can be hired to deliver newspapers. You can call or visit the newspaper office in your area to ask if they are hiring people to deliver papers. If your newspaper office isn’t currently hiring, check back periodically. Doing so will demonstrate that you are serious about the job. You can also ask if they keep applications on file for future openings. While you have to be 14 years old in most states to have a part-time job, one exception is working for your family business. If your parents have a business, ask them if they would be willing to hire you for small tasks. Working a couple hours a day or on weekends for your family business will give you good work experience for when you are old enough to have a different job.

TL;DR in Vietnamese:
Tìm việc làm nông nghiệp. Giao báo. Làm việc trong công ty của gia đình bạn.