Palacios, who is seeking to live out her dream of finishing high school by her 100th birthday, is also the most enthusiastic student in the classroom.
"I feel ready to give it my all. Today is a marvelous day," she said Monday on her first day of high school in the southern state of Chiapas, wearing the school uniform of a white polo shirt with a black skirt and her own personal touch: a pink sweater.
"Dona Lupita," as she is affectionately known, was welcomed with applause from her fellow students at High School Number 2 in the city of Tuxtla Gutierrez, the state capital.
Palacios grew up in poverty in an indigenous village and spent her childhood helping her family farm corn and beans instead of going to school.
As an adult, she went to work selling chickens at market, married twice and had six children.
Along the way, she picked up arithmetic, but never learned to read and write.
"Now I can write letters to my boyfriends," she said with a laugh.
In less than four years, she completed both primary and middle school.
But there was no adult learning program for high school -- so she decided to enroll in a regular public school, with classmates eight decades younger.
Already, she is looking beyond high school: She would like to be a kindergarten teacher someday.
(Except for the headline, this story has not been edited by NDTV staff and is published from a syndicated feed.) Click for more trending news