?Does anyone know what year the Church canonized Mary Magdalene as a saint?
Today’s process of canonization did not exist in the early Church.
Yup, she was designated a saint “pre-Congregation” (ie, before the bureaucratic Vatican process was instituted). This is true of pretty much all the Biblical saints; and yep, pretty much all the Biblical saints have been honored as such since the earliest days of the Church, given saints’ days, and remembered in the Mass or other public prayers of the Church. She comes into ancient hymns and Christian literature, too, just like other Biblical saints.