The Bible does not give Rebekah’s age, though it describes her as a young woman of marriageable age with the maturity to make her own decisions.
Scripture does
not give Rebekah’s age, so any answer is conjecture. We do know that Isaac, her
husband, was forty when they were married (Genesis 25:20). The Hebrew word betulah
is used of Rebekah (Genesis 24:16) and means “maiden,” a young woman of marriageable
age. This indicates that she was young, most certainly younger than Isaac since marriageable age for a woman of that time and place would have been well below forty.
Though she was young,
Rebekah was apparently not very young, as she was given the personal responsibility to choose whether to marry (Genesis 24:58), suggesting maturity and personal
autonomy. All these details show that Rebekah was a young woman with
some independence when she was married, so it would be fair to infer that she was most likely in her late
teens or early twenties. However, that is just an educated guess.
"You're missing the point!" We might say that in frustration when we tell a friend about a work problem, and the friend distracts us with tangential questions about details that don't really matter. Sometimes, people ask about such details in Scripture, but the Bible often doesn't provide those specifics because they don't matter to the bigger picture.
The bigger picture in Genesis is how God kept His promise of a righteous seed (Genesis 3:15) from the beginning of creation to the young nation of Israel. Isaac,
Rebekah’s husband, had been promised that the Savior would come through his
line (Genesis 17:19), yet Rebekah was barren for twenty years (Genesis 25:20–21).
However, as He did with Abraham and Sarah (Genesis 21:1–2), God intervened by
removing Rebekah's barrenness such that two nations would come from her (Genesis
25:23), one of which was Jacob, later named Israel.
As we read these
stories, they should help us remember that God is continually working out His
promise of salvation in our lives. If we could compress our lives to just the details that demonstrate His salvific work, personal details such as age would suddenly become unimportant. Instead, what we should hope to see in our lives is God’s hand in saving us, growing us, and using us to continue His work of salvation
by bringing it to others. While God has already sent His promised seed, Jesus,
there is still more work to do. May we all be a part of salvation’s overarching
story.