Okay, so have you ever heard of a very special lady named Mary? She's kind of like a superhero in the Catholic religion. They call her the "Blessed Virgin Mary" because they believe she was very, very special to God and had a very important job to do.
You see, Catholic people believe that God had a plan to send his son, Jesus, to earth to teach people about love and kindness. But, in order for that to happen, God needed a mom for Jesus. That's where Mary comes in. They believe she was chosen by God to be the mother of Jesus.
But, here's where it gets even more special. Catholic people believe that Mary was so good and pure that she never sinned, even once! They call this being "immaculate." They believe that God made Mary special so that she could be a really great mom to Jesus and help him in his mission to teach people about love.
So, basically, the Blessed Virgin Mary is someone that Catholic people admire and pray to because they believe she was an amazing mom to Jesus and that she's really close to God. They think her life is something to look up to and aspire to and feel like she's looking out for them from heaven.