Why is there a birthday performance when Jiang Yun is not in the circle?

As of August 5, 2022, according to relevant data, Jiang Yun was born in Changzhou, Jiangsu on March 27, 1992. She is a female singer, actress and a second-year student of China women's idol group SNH48. As a preparatory actress, she has not yet entered the entertainment circle. On March 30th, 20 19, Jiang Yun, a member of SNH48TEAMSII, celebrated her special birthday.

Jiang Yun (1992-March 27th), a native of Changzhou, Jiangsu Province, was born in the second phase of SNH48, and is a member of SNH48TEAMSII. His musical works include Love's Lucky Cookie, Black and White Checked Dress, Pioneer and so on. His films include The Journey to the West, White Love, Legend of the White Snake and Xu Xian.