The Feast of the Annunciation, or Lady Day, is normally celebrated on March 25 which is nine months before Christmas. However, this year March 25th was Good Friday, so it is inconceivable to observe such a solemnity on the same day so the liturgical observance of Lady Day was moved.
Eastern Catholic Churches, like the Melkites, observed the Annunciation on March 28th, the day after Easter. In the Roman Catholic Church, the Octave of Easter is eight days, so the Solemnity of the Annunciation was moved to April 4th.
Lady Day used to be the start of the New Year in England from 1155-1752. With calendar changes, the observance moved from April 5th (old Lady Day) to April 6th. One vestige of considering Lady Day as the start of the year is that the United Kingdom's tax year starts on Lady Day.
Sometimes the miracle of the Annunciation gets glossed over in Christmastide or it gets confused with the Immaculate Conception of Mary. As one contemplates the Joyful Mysteries of the Rosary, one gets a glimpse at how the Lord can be surprising and nothing is impossible for God to choose a humble virgin full of grace from the backwater country to be the Mother of God.
As Scripture and Holy Tradition has it, Mary is the first believer and all of her actions point to her Son Jesus. Hence Pope Francis' pearl of wisdom about Mary being like the figurative sunrise for her son (metaphorical sun) Jesus.