Presumption on your part. We do not know when Mary died.
Why is there no tomb of Mary? Why are there no relics of her body? Why are these never even mentioned in history?
We have relics from all the apostles. We have relics of tens of thousands of Christian saints and martyrs. And there have been many, many cases of FAKE relics.
Why the total absence of any relics of Mary from history?
Why didn’t anyone ever even claim FALSELY to have relics of Mary?
Because ALL Christians have ALWAYS believed that Mary was assumed into heaven, body and soul. Even all the potential CROOKS or FRAUDSTERS knew that no one would believe they had relics of Mary, so no one ever made such a claim.