Although her "fiat" to the Archangel Gabriel's message from God was strong and forceful, and although she was her Son's perfect disciple, it is clear from scripture that Mary did not understand all that God and Jesus said and did.
Here again, she shows us how to follow Jesus even if at times we do not understand fully.
We are told that at the annunciation, she pondered on the Angel's message in her heart. After the birth of Jesus, when the shepherds came to adore after being visited by angels, Mary kept what they were saying, reflecting on them in her heart. At the presentation, when Simon prophesied that a sword would pierce her soul, she could not have understood. When as a boy, Jesus disappeared at Passover time and was lost to them for three days, on finding Him, His response that He was in the Temple about His Father's work was beyond her understanding, and she kept these things in her heart, pondering on them.
Mary accepted that what was at work in her Son was a mystery she could never understand, but she took all these things in and reflected on them quietly within herself.
How often do we meet something we do not understand and either reject it or arrogantly try to reduce to terms capable of human understanding?
And yet, just as she grew in discipleship to her Son, learning from Him the Good News He would eventually share with the world, so she must have grown in understanding, for at the Wedding in Cana, when Jesus protested that His time had not yet come, she nevertheless knew that He would reveal His power to those present at her request. Her pondering had led her to understand her Son. And such is the love and respect that Jesus has for His mother, that He does what she asks of Him.