After Our Lady’s death, Our Lord raised Her from her sleep and brought Her to Heaven, sitting Her at His right hand. He had entered her earthly paradise upon His conception; now, she was received into His heavenly paradise.
Then, the Queen took possession of her throne for the first time. She has the highest place in Heaven, the greatest glory, surpassing that of all the angels and saints. There she reigns as daughter of God the Father, mother of God the Son, and spouse of God the Holy Ghost. There she acts as Queen of all Hearts and Mediatrix of all graces. There She will accomplish the will of God in the elect until the end of time.
As Queen, Our Lady exercises a quasi-omnipotent power, in that her requests are as commands for her own Son, in that the angels do her bidding, in that she is the foremost foe of the devil and crushes his head, and finally in that she exercises her motherhood over all the elect, such that she leads them both to heaven and to holiness.
Consider that if Mary is necessary to God (by His will) to accomplish His purposes, then she is all the more necessary for you to achieve your final end. If God cannot accomplish His design for your salvation without Our Lady, then you, who are less than God, certainly cannot accomplish the work of your salvation without His chosen Queen. This is the reason why St. Louis de Montfort says that devotion to Our Lady is necessary for salvation by a what is called a moral necessity. If you want to accomplish it properly, safely, without dangers or risks, then you must accomplish it through the Queen of Heaven and Earth.