Generally speaking, cross-discipline is more difficult than the same major. What jewelry did you study? Is it design art? If it is art design, there are similarities between the arts, because the environmental design exam will be hand-drawn (depending on the school), so it should be no problem to practice more. Other daily work such as sketching, color and English are necessary. Professional knowledge won't involve too much, because you will have to study for another 2-3 years after your promotion.