You are the daughter of Sirius Black who was not in your childhood because he was sent to Azkaban unjustly, so Narcissa and Lucius raised you since your mother had died

Sirius escaped from Azkaban when you were in your 3rd year at Hogwarts and told you and Harry the truth, today some aurors from the Order of the Phoenix came to fetch you at the Malfoy Manor

Upon arriving at the location where the Order of the Phoenix meetings were held, they explained everything to you and Harry