Modesta is lifelong activist, teacher, and art curator. Modesta grew up in Austin, Texas and was an instrumental organizer in the hay-day of the chicano student movements. She was on the board of La Peña, and curated a number of important cultural exhibits and panels for Latinx artists, particularly on U.S. Latina and Mexicana artist unity, collaboration, and exchange. She was an founding member of MAS (Mujeres Artistas del Suroeste), a component of the umbrella group LUCHA (League of United Chicano Artists) and an organizer in the Farm Workers March of 1966. She successfully pushed for bilingual education and cultural engagement at Sanchez Elementary School where she was a teacher for many years.