A couple of years ago, someone on a web forum tried to bait me into an argument over Mary's role in the Catholic church. I ignored the taunts at the time, though her posts demonstrated a rather aggressive ignorance of the subject.
Since then, I've felt a pang of guilt for leaving the Blessed Mother out dry. She would never do that to me--and that explains much about her role.
First, Catholics do not worship Mary. We venerate her. There's a difference. Veneration is the recognition that Mary's life and role in the life of Jesus Christ places her in a unique place in heaven. If heaven has a hall of fame, whe was the initial inductee as voted on by the Father, the Son, and the Holy Spirit. As such, she deserves our due respect.
Second, we honor the life of faith she lived. At a very young age, probably 15-18, the Archangel Gabriel called her to suffer for God's sake, to become pregnant out of wedlock in a time and place that such was not an accepted circumstance, and to become the primary caregiver of God's only Son. She said, "Yes." She trusted God with her entire life, setting an example of faith few have approached since.
Third, she is a mother. She stood at the foot of the Cross and watched her only child die an ignoble death of torture. She allowed Him to die, to suffer, because of her astonishing faith in Him. Still, her heart bled figuratively while His bled literally. As a loving mother, she is our best ally and advocate in heaven. We ask her to intercede for us, as we do with all our saints. Thinks of when school calls home and tells your mother that you screwed up. Didn't she sugar-coat it when she told your Dad? Or when you wanted something really, really special for your birthday--did you tell Mom or Dad? Those of us lucky enough to have two parents, or even a loving step-mother, probably approached Mom first. Why? Because. That's just the way it is. My own kids go to their step-mother with EVERYTHING bad. They ask her for help; they give her the bad notes from school. She's a mom.
Mary is our Mom before Jesus Christ and God. How could any Christian NOT go first to her? We go to her when we have sinned, asking her to smooth the path to Almighty God. She is like a lawyer, but only if the lawyer loves us.
Finally, Fr. Corapi says, "If she's good enough for Jesus, she's good enough for you."
If there is still any confusion, please feel free to comment. I never tire of talking about the Blessed Virgin.