She only told her personal servant and handmaid that she is a woman, but the crown prince knew about it from the begining. He just recently confessed to her.
Her attendants think she is a man pretending to be a woman.
Officialy, Sir Austin recieved a title and moved to the countryside after his sister became the crown prince's fiancee. That's what Tozen believed until he saw her swordsmanship and recognized it as Austin's. He now believes that she is Austin pretending to be a woman. The crown prince's attendant was here too, and he thinks that means the crown prince is gay, since he saw the two together and the prince's feelings looked genuine.
Irregular Empress