If she is still living, you should start by asking her for the information.
Thank you for posting your request on History Hub!
Beginning September 27, 1906, the responsibility for naturalization proceedings was transferred to the Federal courts. It took time for the lower courts to let go of the practice, so researchers may need to look at lower courts if the National Archives does not maintain a record of naturalization from the early-mid 20th century.
In general, naturalization was a two-step process that took a minimum of five years. After residing in the United States for two years, an alien could file a "declaration of intention" ("first papers") to become a citizen. After three additional years, the alien could "petition for naturalization" (”second papers”). After the petition was granted, a certificate of citizenship was issued to the alien. These two steps did not have to take place in the same court.
If a naturalization took place in a Federal court, naturalization indexes, declarations of intention (with any accompanying certificates of arrival), and petitions for naturalization will usually be in the National Archives facility serving the state in which the Federal court is located. No central index exists. To ensure a successful request with the National Archives, researchers should include: the name of petitioner (including known variants); date of birth; approximate date of entry to the US; approximate date of naturalization; where the individual was residing at the time of naturalization (city/county/state); and country of origin.
Due to the COVID-19 pandemic and pursuant to guidance received from the Office of Management and Budget (OMB), NARA has adjusted its normal operations to balance the need of completing its mission-critical work while also adhering to the recommended social distancing for the safety of NARA staff. As a result of this re-prioritization of activities, you may experience a delay in receiving an initial acknowledgement as well as a substantive response to your reference request. We apologize for this inconvenience and appreciate your understanding and patience.
In most cases, the National Archives will not have a copy of the certificate of citizenship. Two copies of the certificate were created – one given to the petitioner as proof of citizenship, and one forwarded to the Immigration and Naturalization Service (INS).
All INS records are now overseen by the US Citizenship and Immigration Services (USCIS). USCIS maintains duplicate copies of court records (including the certificate of citizenship) created from September 27, 1906 through March 31, 1956 within Certificate Files (C-Files). Beginning on April 1, 1956, INS began filing all naturalization records in a subject’s Alien File (A-File). C-Files and certain A-Files may be requested through the USCIS Genealogy Program.
We hope this is helpful. Best of luck with your family research!