How Old Was Rebecca When She Married Isaac?

According to some people, it seems Rebecca was three when she married Issac. As disgusting as this may be, the claim randomly arises in groups so it is important to address. Firstly, it is important to remember that prophets too are sinful so even if this was true(something we believe we can heavily contest) it would not mean the act was justified in any capacity.

This claim comes from the book of Genesis which states the following:

Sarah was 90 when Abraham was 100 (Genesis 17:17)
Abraham was 100 when Issac was born (Genesis 21:5)
Sarah died at 127 (Genesis 23:1-2)
Issac was 37 when his mother Sarah died (Sarah was 90 when she had Isaac. 127(total age)-90(when she had him)=37

Based on this, it seems Sarah was 90 when Issac was born(Issac was born when Abraham was 100, Sarah was 90 when he was 100). Issac would be 37 then, when his mother died(127-90=37). Abraham told of Rebecca's birth(Genesis 22:20-23) and Sarah died after, in Genesis 23:1-2. We then see that Issac married Rebeccah at 40(Genesis 25:20). Have you seen the issue? There is a time gap between the death of Sarah and the birth of Rebecca that we do not know of. It is completely based on an assertion that it happened instantly after which may not be the case, for all we know it was decades after. Here are some graphs for a better perspective below.

Abraham lived 175 years: "Abraham lived a hundred and seventy-five years Then Abraham breathed his last and died at a good old age, an old man and full of years; and he was gathered to his people," (Genesis 25:7-8 KJV).

Sarah lived 127 years: "Sarah lived to be a hundred and twenty-seven years old. She died at Kiriath Arba (that is, Hebron) in the land of Canaan, and Abraham went to mourn for Sarah and to weep over her," (Genesis 23:1-2 KJV).

Issac lived 180 years: "And the days of Isaac were an hundred and fourscore years," (Genesis 35:28 KJV).

Abraham is 100 years old when Issac had him: "And Abraham was an hundred years old, when his son Isaac was born unto him," (Genesis 21:5 KJV).

Sarah is 90 years old(Sarah is ten years younger than Abraham): "Then Abraham fell upon his face, and laughed, and said in his heart, Shall a child be born unto him that is an hundred years old? and shall Sarah, that is ninety years old, bear?" (Genesis 17:17 KJV)

Rebecca is born: "And it came to pass after these things, that it was told Abraham, saying, Behold, Milcah, she hath also born children unto thy brother Nahor; Huz his firstborn, and Buz his brother, and Kemuel the father of Aram, And Chesed, and Hazo, and Pildash, and Jidlaph, and Bethuel. And Bethuel begat Rebekah: these eight Milcah did bear to Nahor, Abraham's brother," (Genesis 22:20-23 KJV).

Isaac was 37 when Sarah died(Sarah was 90 when she had Isaac(Genesis 21:5 & Genesis 17:17). 127[total age](Genesis 23:1-2)-90[when she had him]=37):

Rebecca is an unknown age:

Isaac and Rebecca marry. Isaac is 40, Rebecca's age is unknown: "And Isaac was forty years old when he took Rebekah to wife, the daughter of Bethuel the Syrian of Padanaram, the sister to Laban the Syrian," (Genesis 25:20 KJV).

Based on the following graph, we have little idea on the age of Rebecca. All we can say is she was younger than Isaac, but there is no reason to think she was 3.