What is your belief about the importance of the Virgin Mary to all humanity in our search for God's mercy? I believe that she is a very important person because of her miraculous appearance to the three shepherd children in Fatima, Portugal. Her apparitions and the messages she brought from heaven transformed the lives of the three shepherd children and countless other people who came in contact with them or knew about them. -- J. A. (London)

Such appearances are common in human history. For example, Kwan Yin has appeared to many people. So has the Phrygian Mother Goddess. So has Avalokiteshvara. And so has Maria, not to mention many other "saints." Goddesses and mother goddesses are extremely common in human history. 

Mary was voted to be the Mother of God in 431 AD (at Ephesus). This was a new development. It is not anticipated in Scripture (except negatively, as in Jeremiah 7:18, 44:17-19,25).

I would encourage you to do some research. One book you might consider is here. Another, which helped me think about these issues, may be found here. I hope these assist you in your study.