mendoza's family moved to arizona shortly after so that her father could help organize copper workers into the miners smelting workers union, where he gained the position of officer. after their time in arizona, mendoza's family moved back to california and settled in campbell, california, then a township of san jose. there, she attended campbell grammar school, and campbell high school. it was during her time in high school that mendoza began organization drives of various kinds, after witnessing her father do it for so many years. as a freshman at campbell high school, mendoza successfully petitioned her classmates and faculty members for the addition of a spanish club on campus.