This year the Annunciation was moved from its usual date (March 25) because that fell during the octave of Easter, and Easter supersedes all other feasts.
It was fortuitous, though, because the Annunciation was celebrated the day after Divine Mercy Sunday. The special grace of the Divine Mercy feast is not only the forgiveness of sins, but the grace of conversion in particular--to turn from sin and live a new life. It's an Easter grace, because through his death and resurrection Jesus merited for us the grace to die to sin and rise to new life with him.
Mary has a special place in all this. There's a great book called Mary in the Mystery of the Covenant by Fr. Ignace de la Potterie. He explains that when Mary said "yes" to God at the Annunciation, she was saying it in a wholehearted, enthusiastic way. That's not just a pious thought, but backed up by some good Scriptural scholarship. Potterie tells us that the Greek form of the verb used when Mary says, "Let it be done to me.." is an optative. It's a form used only rarely in the New Testament, and it is used to express a joyous desire to do something. The "yes" of Mary was a joyous "yes," one that she said with an eagerness to do what God was asking of her.
Mary, obtain for us, too, your eagerness and joy in doing God's will!