The same angel who appeared to Zacharias, appeared to Mary, the future mother of Jesus, and the appearance frightened her, as it did Zacharias. As the angel told Zacharias, so the angel told Mary not to fear, and Luke shows that the angel explained himself,
“Then the angel said to her, ‘Do not be afraid, Mary, for you have found favor with God. And behold, you will conceive in your womb and bring forth a Son, and shall call His name JESUS’” (Luke 1:30-31).
Even as Zacharias and his wife would have a son, so Mary would have a son, but without a husband to beget the child.
The entire history of the world pointed to this moment, and I am sure that Mary did not realize just how momentous an event this was, and the rest of the history of the world would be built upon this moment.
Mary accepted what the angel said, and the world has never been the same since.
Let us likewise, accept what the word of God says, and we shall never be the same, and we will touch the lives of many other people and wonderful things shall happen.