Mary was in communion with all the events of Jesus' life

Mary was apparently not present at the Jordan at the time of Jesus' baptism, but she communed with the significance of that event by her whole life. Pope John Paul II made the baptism of Jesus in the Jordan the first luminous mystery of the Rosary.

The Jordan River had a symbolic role as the border with the promised land of Canaan (Joshua 6). To immerse oneself in the Jordan was to symbolically repeat the whole spiritual journey of Israel, obeying God's command, leaving Egypt, staying at Mount Sinai, walking through the desert, while being supplied with manna each day.

Mary personally made this spiritual journey. She knew that she was loved by God, who looked after her (Lk 1:48). She knew that she had been chosen by God, who made a covenant with her. We can compare the Annunciation with the Covenant at Mount Sinai. Mary too set out on her own journey, trusting God.

Encyclopédie Mariale