1.39 Mary is not God – so, why all this devotion to her?

Above all with the Hail Mary, the prayer with which the Church asks the intercession of the Virgin. Other Marian prayers are the Rosary, the  Akathistos hymn, the Paraclesis, and the hymns and canticles of diverse Christian traditions. [CCCC 563]

Hail, Mary,
full of grace,
the Lord is with you.
Blessed are you among women,
and blessed is the fruit of your womb, Jesus.
Holy Mary, Mother of God, pray for us sinners,
now and at the hour of our death. Amen.

In Latin:
Ave Maria, gratia plena.
Dominus tecum.
Benedicta tu in mulieribus,
et benedictus fructus ventris tui, Jesus.
Sancta Maria, Mater Dei,
ora pro nobis peccatoribus,
nunc et in hora mortis nostrae. Amen.

[Youcat 480]

1. In the name of the Father …
2. Apostles’ Creed
3. Our Father
4. Three Hail Marys
5. “Glory be to the Father, and to the Son, and to the Holy Spirit, as it was in the beginning, is now and ever shall be, world without end. Amen.”
6. Five decades, each with one Our Father, ten Hail Marys, and a Glory Be to the Father.

The complete Rosary consists of Joyful, Luminous, Sorrowful, and Glorious Mysteries.

• The Joyful Mysteries (Monday, Saturday)
  1. The Annunciation
  2. The Visitation
  3. The Nativity
  4. The Presentation of the Child Jesus in the Temple
  5. The Finding of the Child Jesus in the Temple
      
• The Luminous Mysteries (Thursday)
  1. The Baptism in the Jordan
  2. The Wedding Feast at Cana
  3. The Proclamation of the Kingdom of God and Repentance for Sin
  4. The Transfiguration
  5. The Institution of the Holy Eucharist
      
• The Sorrowful Mysteries (Tuesday, Friday)
  1. The Agony in the Garden
  2. The Scourging at the Pillar
  3. The Crowning with Thorns
  4. The Carrying of the Cross
  5. The Crucifixion
      
• The Glorious Mysteries (Wednesday, Sunday)
  1. The Resurrection
  2. The Ascension
  3. The Descent of the Holy Spirit
  4. The Assumption of the Blessed Virgin Mary
  5. The Crowning of the Blessed Virgin Mary as Queen of Heaven

[Youcat 481]

It is a singular kind of devotion which differs essentially from the cult of adoration given only to the Most Holy Trinity. This special veneration directed to Mary finds particular expression in the liturgical feasts dedicated to the Mother of God and in Marian prayers such as the holy Rosary which is a compendium of the whole Gospel. [CCCC 198]

No. Only God can be worshipped. But we can revere Mary as the Mother of our Lord.  

By worship we mean the humble, unconditional acknowledgment of the absolute superiority of God over all creatures. Mary is a creature like us. In faith she is our Mother. And we should honor our parents. There is a biblical basis for this, since Mary herself says, “For behold, henceforth all generations will call me blessed” (Lk 1:48b). so the Church has Marian shrines and places of pilgrimage, feast days, hymns, and prayers, for instance, the Rosary,  It is a compendium of the Gospels. [Youcat 149]