When did you discover that Jade Butterfly was a princess?

Qin Guifei took Song Yudie into the palace and wanted to give her son and mother lock to Song Yudie. Unexpectedly, the son-mother lock in her hand is just a pair worn by Song Yudie. Qin Guifei recognized that Song Yudie's golden lock was made by her, so she immediately took Song Wusao into the palace and asked Song Yudie about her life experience.