Junior high school education can learn jewelry design, and learning a new skill is not limited by education. Some majors need a certain degree to learn, but art teachers usually start from the most basic, and most of them learn practical operations. There's nothing to worry about.
However, it's best to study jewelry design and improve your education in Peng Zhong. After all, looking for a job in the future depends not only on ability but also on education. Having a degree is very helpful for your future development.