Can someone explain the men's gymnastics Junior Olympic Program?

How do the junior olympics work? If you're at a certain age do u start at a certain level? I've tried researching to figure it out but it just confuses me more. One website said guys always start at level one, and progress each year, but that seems kind of weird because what if you're better than level one? Can someone explain exactly how everything works? Thanks.|||competition starts at like level 4... you dont wait a year to move up... you move up when you learn the skills for the next level. No generally it is not by age...