"Then the angel said to her, Do not be afraid, Mary, for you have found favor with God. And you will conceive in our womb and bring forth a Son, and shall call His name Jesus. He will be great, and will be called Son of the Highest; and the Lord God will give Him the throne of His father David. And He will reign over the house of Jacob forever, and of His kingdom there will be no end." (Luke 1:30-33)
Mary was just a teenager engaged to Joseph when the angel of the Lord appeared to her. He told her what was going to take place very soon and that her life would be changed forever. That is a lot of information for a young woman to absorb. Still, her answer to the angel was, "Behold the maidservant of the lord! Let it be to me according to your word." (Luke 1:38) Mary simply made herself available to God and a Savior was born.