Because of a lack of authentic infancy narratives, we can only speculate about what things Mary kept and reflected on in her heart. Luke tells us that she wondered how the pregnancy would come about. Matthew tells us that Joseph took her into his house. The actual nativity is regarded as miraculous, setting aside practical considerations like the arduous journey to Bethlehem days before delivery, the absence of women at parturition, the need for purification and circumcision.
Mary "the simple woman of Nazareth" was God's favored one before we we dubbed her "Theotokos." Her child, though laid in a manger, was God's beloved Son before we anointed him "Christus." Both Mary and Jesus were created in the true and humble image and likeness of God among us. Humbly, Mary said, "I am the servant of the Lord... Do whatever he tells you."  Jesus said, "I have come not to be served  but to serve... I have given you a model... Love one  another."
From the Gospel to life, from life to the Gospel.