In the 1851 census, it has that she is from Claypole, which may not be the same couple that you are looking for. In the 1851 Surrey census, she is 65, and they have a 21-year-old daughter Elizabeth. In the 1841 Kent census, she is 50, and Elizabeth is not listed.
I see her age on the tombstone, but they can be incorrect. They married in 1814, the image of their marriage record states that it was with the consent of a parent. That means she had to be under 21 years old at the time.
It is possible that two different families were thought to be one.