A 79-year-old Texas woman who went back to school on the advice of her great-grandson said she has earned her GED certificate after three years of study. Tomasa Herrera of Fort Worth said the road to her high school equivalency certificate was beset with obstacles during the past three years including eye surgery, appendicitis, a broken leg and paralysis from the waist down, the Fort Worth Star-Telegram reported Tuesday. "To this day I don't know what to say about it," Herrera said of obtaining her GED. "Deep down inside me, I'm excited. There's just not words to express." "Math was the hardest part for me; I failed it three times," she said. Herrera said she was inspired to get her degree while struggling to help her great-grandson with his homework. "He told me, 'You need to go back to school, Grandma,'" Herrera said.