Tacitus records Occia's fifty-seven years as chief Vestal and her death in 19 CE in unusual detail, but does not state when she was born or when she entered the Vestal order as a girl.
What would resolve this An epigraphic or documentary record of her family and the year she was chosen for the Vestal order as a girl.
OpenRoman epigraphy, history of the early PrincipateRobin Lorsch Wildfang, Rome's Vestal Virgins: A Study of Rome's Vestal Priestesses in the Late Republic and Early Principate