[1] On 10 August 1903 she entered the novitiate with the Mercedarians at the convent of Vera Cruz and assumed the religious name of "Margarita María".

She would later teach and serve as a principal though suspended this for a brief period in 1922 when she developed a duodenal ulcer that would continue to plague her for the remainder of her life.

[1][2] The nun was later named as the superior of her house on 16 April 1927 while on 11 November 1928 she arrived in Saipan in the Northern Mariana Islands on her first ever trip to the missions.

On 17 May 1930 she received approval to establish a religious order based in Bérriz at the house and on 30 July 1931 founded it as the first superior general - she served as such for the remainder of her life.

[1] She made two more trips to the South Pacific but an ulcer led to stomach cancer and she was forced to return home to recuperate.