Without Mary we would not have Jesus, so she is central to the saving plan of God. Before the world began Jesus is predestined to unite heaven and earth as God made man. Mary is chosen and predestined as part of that same mystery. Mary is preserved from the damage of original sin for the sake of Jesus.
Then in the Annunciation Mary welcomes the Messiah on behalf of all humanity, and so God becomes man through her co-operation and in her womb. Her complete “yes” to God in Christ shapes her whole life. It leads her to stand at the foot of his cross where she co-operated with his Sacrifice through her faithfulness and her prayer. As he was dying Jesus gave Mary to all of us as Mother of the Church. She is the first to share in the resurrection of her Son when she is taken to heaven in her body as well as her soul. Mary continues her unique relationship with Christ and with the rest of the Church from her place in heaven.
We ask her prayers because she is closest to her Son and she is the best of teachers about following Jesus. "Do whatever he tells you" (John 2,5). As Queen of the angels and saints Mary is a great sign of hope to all believers.