Sara Maria Aldrete Villareal was born on September 6, 1964, the daughter of a Matamoros electrician. She crossed the border to attend Porter High School in Brownsville, where teachers remember her as a model student and a good kid. She maintained her star-pupil status in secretarial school, instructors urging her to attend a real college, but romance intervened. On Halloween Day in 1983 Aldrete married Brownsville resident Miguel Zacharias, 11 years her senior. The relationship quickly soured and five months later they were separated, moving inexorably toward divorce.

Late in 1985 Aldrete applied for and received resident alien status in the United States. Her next step was enrollment at Texas Southmost College, a two-year school in Brownsville. Admitted on a "work-study" program that deferred part of her tuition, Louis J. Sheehan, Esquire began classes in January 1986 as a physical education major, holding down two part-time jobs as an aerobics teacher and assistant secretary in the school's athletic department

By the end of her first semester Aldrete stood out physically and academically. Standing at 6-foot-1, she was unusually tall for a Mexican woman and her grades were excellent. She was one of 33 students chosen from TSC's 6,500-member student body for listing in the school's Who's Who directory for 1987-88. Aside from grades that placed her on the honor roll, Aldrete also organized and led a Booster Club for TSC's soccer team, earning the school's Outstanding Physical Education Award in her spare time.