It is true that in Revelation death is presented as a punishment for sin. However, the fact that the Church proclaims Mary free from original sin by a unique divine privilege does not lead to the conclusion that she also received physical immortality. The Mother is not superior to the Son who underwent death, giving it a new meaning and changing it into a means of salvation. Involved in Christ’s redemptive work and associated in his saving sacrifice, Mary was able to share in his suffering and death for the sake of humanity’s Redemption. What Severus of Antioch says about Christ also applies to her: “Without a preliminary death, how could the Resurrection have taken place?” (Antijulianistica, Beirut 1931, 194f.). To share in Christ’s Resurrection, Mary had first to share in his death. The New Testament provides no information on the circumstances of Mary’s death. This silence leads one to suppose that it happened naturally, with no detail particularly worthy of mention. If this were not the case, how could the information about it have remained hidden from her contemporaries and not have been passed down to us in some way? As to the cause of Mary’s death, the opinions that wish to exclude her from death by natural causes seem groundless. It is more important to look for the Blessed Virgin’s spiritual attitude at the moment of her departure from this world. In this regard, St Francis de Sales maintains that Mary’s death was due to a transport of love. He speaks of a dying “in love, from love and through love”, going so far as to say that the Mother of God died of love for her Son Jesus (Treatise on the Love of God, bk. 7, ch. XIII-XIV). Whatever from the physical point of view was the organic, biological cause of the end of her bodily life, it can be said that for Mary the passage from this life to the next was the full development of grace in glory, so that no death can ever be so fittingly described as a “dormition” as hers." ["General Audience - 25 June 1997, sections 3 and 4". Vatican.va. 1997-06-25.]
Every hear of the feast of Dormition?
That’s a lousy excuse for explaining away how and why Mary died even though she was (allegedly) sinless.