Many Catholics confuse Mary's Immaculate Conception with the Incarnation of Jesus. One of my daughters had her sixth grade teacher (at a Catholic school no less) correct her when she said the Immaculate Conception happened when Mary was conceived without original sin in the womb of her mother Ann. Tara was absolutely right, but it took a handout from the Basilica Shrine of the Immaculate Conception to convince the teacher she was mistaken. Good for Tara for not backing down. And good for the teacher who correctly instructed her students about the feast.
Just goes to show, you are never too old to learn and that we need to study the doctrines of our faith.
All of us are conceived with original sin. Why? Because Adam and Eve couldn't give us what they didn't have.
Think of it this way.
Before original sin, Adam and Eve's DNA was perfect. They would never die, they were totally physically and mentally integrated: no defective genes, no sensitivity to physical ailments or mental illness. In other words, they were perfect, both physically and emotionally.
Then they listened to the devil, a murderer and liar from the beginning and a quack who sold them a big dose of snake oil. He injected them with a genetic fault that infected every one of their cells, one that destroyed their original integrity (their "hard drive" in computer lingo) and destroyed their ability to pass on their original perfection. So, instead of that, they gave all their children the defective gene, one that inclined them toward sin and weakness.
Mary however, was saved from this genetic catastrophe by the great physician who corrected the fault in the egg cell of her mother, Ann, and the sperm cell of her father, Joachim. So, when she was conceived, she received the same perfection given to Adam and Eve at the beginning, which is why she's called the "New Eve."
Today is a great feast day, one that is so important the Church makes it one of the few "holy days of obligation" that require Catholics to attend Mass as if it were Sunday. Who could object to honoring this so glorious mother, especially in the holy season of advent when we focus on the perfection of her Son? Note that the feast occurs nine months before the date when Catholics traditionally celebrate Mary's birthday, September 8th.
So enjoy the feast. Have a special treat with the family and praise the Holy Mother of God! "O Mary, conceived without sin, pray for us who have recourse to thee."
Happy feast day!