"Why do Catholics worship Mary?" That is a question that most Catholics will be asked, as many people have this misconception. However, Catholics do not worship Mary, and they also do not pray to Mary.
Let's take a look at the Hail Mary.
"Hail Mary, full of grace,
The Lord is with you."
This first part comes from the Angel Gabriel's words when he came to speak to Mary. "And coming to her, he said, 'Hail, favored one! The Lord is with you' " (Luke 1:28).
"Blessed are you among women,
and blessed is the fruit of your womb, Jesus."
This part comes from the words of Elizabeth when Mary went to visit her. Luke 1:41-42 says, "When Elizabeth heard Mary's greeting, the infant leaped in her womb, and Elizabeth, filled with the holy Spirit, cried out in a loud voice and said, 'Most blessed are you among women, and how blessed is the fruit of your womb.' " Mary is indeed very blessed, and we should recognize that. Mary herself said in Luke 1:46-49, " 'My soul proclaims the greatness of the Lord; my spirit rejoices in God my savior. For he has looked upon his handmaid's lowliness; behold, from now on will all ages call me blessed. The Mighty One has done great things for me, and holy is his name."
Holy Mary, Mother of God,
pray for us sinners,
now, and in the hour of our death.
When we say this last part, we are simply asking Mary for prayers, not praying to her. We do not pray to Mary believing that she is the one who will cause something to happen. That would be idolatry. However, we do ask for her intercession, just like we would ask a friend, priest, or church member to pray for us. I have not yet done an in depth study on Revelation (we should be doing one at church soon), but there seems to be evidence that people do worship and pray in heaven.
Finally, Mary was the first one who accepted Jesus as her savior. She is also a beautiful example for women in the way she completely submitted herself to God's will: " 'Behold, I am the handimaid of the Lord. May it be done to me according to your word" (in Luke 1:38). That is an incredible attitude, and we should all strive to have that mindset and be more like Mary.
So no, Catholics do not worship Mary. We adore her and admire her as the Blessed Mother of the Lord. As a woman in our Bible study said, Mary does not take away from Jesus - she points to Jesus. Our priest made a great point at the Feast of the Immaculate Conception. He said that that we all love and adore our mothers, and it makes us happy to see other people who love our moms and say good things about them. Wouldn't Jesus also love seeing people admire and appreciate his mother?