We do not have an actual date for when the event took place. The reason for this is that this event started off in such a private and isolated manner. Not a simple matter, but a private and isolated manner when an angel sent from God comes to a very young woman and tells her she is highly favored.
Today the Lectio passage is the Annunciation to Mary of an act that changes everything for all time. God is going to become a man. The Divine Trinity is going to become an active intimate participant in what it means to be a created human being.
Words really cannot describe this event. God self describes it through the Apostle John when John writes the Word became flesh and dwelt among us. The Word, the Logos, the very meaning of life, love, and ultimate living. God became a living person in order to be a dying person.
And the young girl, the things she will face, the awkwardness, the risk to life, the potential shame and rejection do not matter. I believe the name Mary is a synonym for faith. Through her womb, God was fashioned into a man. In Mary, God was seemingly fragile and dependent. Again not the word seemingly, for God is God in whatever form or fashion God chooses to be.
Yet, since we know the high points of the story of this life, we know it is to a journey of suffering, rejection, hostility, pain, and cruel death. These are negative things we either have experience or will experience in our lives in some form or fashion. What we cannot ever comprehend or grasp is what God felt, experienced, or endured to: “but emptied himself, taking the form of a slave, being born in human likeness. And being found in human form, he humbled himself and became obedient to the point of death– even death on a cross. (Phil. 2:7-8 NRS)
Because of this, not only Mary but we too are highly favored.