After Gabriel went to Zacharias to reveal to him that he would have a son, whom we know as John the Baptist, God then sent Gabriel to Mary with an even greater announcement, that she would have a son, although not yet fully married.

Imagine that you are Mary and you question the angel, but then he explains how you shall have a son, and just who that son would be,

Then Mary said to the angel, “How can this be, since I do not know a man?” And the angel answered and said to her, “The Holy Spirit will come upon you, and the power of the Highest will overshadow you; therefore, also, that Holy One who is to be born will be called the Son of God” (Luke 1:34–35).

You are a woman of no significance, but then an angel visits you, announcing that you shall give birth to the Son of God! What would go through your heart when you heard such an announcement?
Yet, if any of us do the will of her son, He considers us His mother, brother, or sister!