She was born circa 1789. Her father was Jose Ignacio Perez, and her mother was Antonia Gertrudis Longoria.
In 1791, she lived in Mier in household number 26. The church census recorded that she was a young child, casta, and 2 years old. Her household included 5 people:
Jose Ignacio Perez, married, casta, age 48.
Antonia Gertrudis Longoria, married, casta, age 31.
Maria Alexandra Perez, a young child, casta, age 7.
Jose Julian Perez, a young child, casta, age 3.
Antonia Maria Perez, a young child, casta, age 2.