In Pius XII’s dogmatic statement, the phrase “having completed the course of her earthly life,” leaves open the question of whether the Virgin Mary died before her assumption or whether she was assumed before death; both possibilities are allowed. Mary’s assumption is said to have been a divine gift to her as the ‘Mother of God’. Ludwig Ott’s view is that, as Mary completed her life as a shining example to the human race, the perspective of the gift of assumption is offered to the whole human race.[26]
"In Ludwig Ott’s Fundamentals of Catholic Dogma he states that “the fact of her death is almost generally accepted by the Fathers and Theologians, and is expressly affirmed in the Liturgy of the Church”, to which he adduces a number of helpful citations, and concludes that “for Mary, death, in consequence of her freedom from original sin and from personal sin, was not a consequence of punishment of sin.[27] However, it seems fitting that Mary’s body, which was by nature mortal, should be, in conformity with that of her Divine Son, subject to the general law of death”.[27]
The point of her bodily death has not been infallibly defined, and many believe that she did not die at all, but was assumed directly into Heaven. The dogmatic definition within the Apostolic Constitution Munificentissimus Deus which, according to Roman Catholic dogma, infallibly proclaims the doctrine of the Assumption leaves open the question whether, in connection with her departure, Mary underwent bodily death; that is, it does not dogmatically define the point one way or the other, as shown by the words “having completed the course of her earthly life”.[20]" Wiki Pedia
This is my understanding. As to what I believe, the Tradition. Nevertheless I was not there, as far as I see here on earth, all die. As to what God can do? Anything.