The show ran from 1962 - 1971. She was 29 in 1962 and was 38 when the show ended in 1971.
And "The Beverly Hillbillies" had good ratings, even in 1971. It was canceled anyway. CBS thought that the show was not sophisticated enough for the "hip" audience it wanted to attract.
The same thing happened to "Green Acres".
And somehow the very next day she was 81.
RIP she was always sweet on that show.