I did the Google thing, and found a list of women running for Vice President. I didn’t put U.S. in the search terms, so the list is planet-wide.
The first time?
1884 Marietta Lizzie Bell Stow, United States of America
She was the running-mate of Belva Ann Bennett Lockwood of the The Equal Rights party.
I don’t Palin really was so bad as to poison a well going back 128 years. Good try though, Republicans.