Mary is sometimes called the “new Eve”. While your Jehovah Witness friend probably wasn’t refering to that, I do believe that the first woman created perfectly by God, Eve, was God’s first choice to be our mother. I don’t think God created the world intending us to fall into sin, (although I believe He knew it would.) But as Eve and Adam fell, bringing sin into God’s perfectly created world, God promised a savior. If your friend was implying that some other woman was really God’s first choice to bring the world that savior, I think that’s wrong. If your friend meant to imply that God created Eve perfect at the dawn of creation, and that Mary is the New Eve, I think he’s right.