To deny God to put the Blessed Virgin Mary, or anyone else for that matter, dead or alive, ANYWHERE HE WANTS THEM, is to DENY that He is God and to DENY so many of His works as they are proclaimed in the Bible that it makes a person a heretic! Ah, from your comment, it appears that you believe in predestination, because that is exactly what you described.
You are confusing 'predestination' with 'omnipotence'.When we are created by God, and our soul and spirit are united to our body, God asks us: "Will you Serve?" (Thus, Lucifer's: "Non Servium", I will not serve.) If we say, "yes", He asks: "At what level", the highest level obviously being martyrdom. It is also true that if we say, "no", then He will again ask, "At what level?" At Lucifer's 'Non Servium' level, he obviously said, "Not only will I not serve, but I will bring all of my followers, human and demonic, against You with our shared 'Non Servium'."
God places us where we have, by our own free wills in this encounter, told Him He needs to put us. Either where we will serve Him or where He can protect Himself and those who will serve Him against the ones who won't. Since He gives us a free will, to be true to Himself, He must allow us to use it no matter how much it may hurt Him or us. This is the Meekness and Humility of our God! His Power as He told St. Paul is made perfect in our infirmity.