Of course, the certificate of China Calligraphy Association is higher than that of other local calligraphy associations, that's all.
Calligraphy, as a hobby, is a good choice if practiced well, which will help you to participate in social activities at school.
As for the grading test, it is similar to the piano grading test, and it is all about hands-on ability. No matter how high the test level is, it is important to look at your own hands.