The Virgin Mary is the mother of Jesus Christ, who over a billion people as God's son, explaining why she is considered one of the most important people ever. It is not clear when she was born, but going by the Bible we can guess about 30 20 BC. She probably died around 40 AD, maybe later though. There is not a great deal of writings on her in the bible, making it hard to verify when she was alive.
She was an important figure as she was "the Mother of God" as the Bible says. She became pregnant with Jesus by the "power of the Holy Spirit." She was visited by Gabriel, God's favorite angel and told she would give birth to the Messiah.
Just as important as her raising the founder of the Christian religion is how she is glorified today. Her title Mother of God was challenged in the 4th century when some argued that she was the mother of Jesus, not that of God. The Catholic and Orthodox churches established that she was in fact the Mother of God.
There were controversies as she was called the "Ever-Virgin Mary," yet the Bible talks of Jesus having brothers and sisters that do not appear to be divine and also God's immediate children. She is still, however considered the "Ever-Virgin"
She is glorified very highly, especially in the Catholic Church. Examples of this are the prayer "Hail Mary," the feast day "The Immaculate Conception," and numerous shrines. Her mere existence , and perhaps what her son, Jesus, earned her importance to Christians.