Since net s are banned in South Korea, we can't say anything about the minimum age. https://oppa.im/%EC%95%88%EC%A0%84%ED%95%9C-%EA%B2%8C%EC%9E%84%EC%9D%98-%EC%B2%AB%EA%B1%B8%EC%9D%8C-%EB%A8%B9%ED%8A%80%EB%B0%A9%EC%A7%80-%ED%86%A0%ED%86%A0%EC%82%AC%EC%9D%B4%ED%8A%B8/