Pettis is a 2018 graduate of the University of California, where she competed as an infielder on the Bears' softball team. She was a 2015 member of the U.S. Women's Junior National Team and earned All-Pac-12 Honorable Mention honors and Pac-12 All-Freshman team honors the same year. In 2016, Pettis was named a Pac-12 All-Academic Honorable Mention selection.