She was born circa 1778. Her father was Jose Cayetano Lopez, and her mother was Maria Antonia Gonzalez.
In 1782, she lived in San Juan Bautista del Cojo in household number 134. The church census recorded that she was a young child, española, and 4 years old. Her household included 6 people:
Jose Cayetano Lopez de Jaen, married, español, age 34.
Maria Antonia Gonzalez, married, española, age 26.
Juana Maria Lopez, a young child, española, age 4.
Maria Gertrudis Lopez, a young child, española, age 3.
Jose Rafael Lopez, a young child, español, age 2.
Juan Antonio Santos, a youth, español, age 15.