For whatever reason, she is listed as being born in Germany in censuses with her husband. She is also in the 1900 census with her parents with an incorrect birth year. Her obituary has her correct birth information.
Sources
"California, County Marriages, 1850-1952," database with images, FamilySearch (https://familysearch.org/ark:/61903/1:1:XL8J-VTT : 8 December 2017), Frederich Heil and Mary Sabott, 10 Jun 1899; citing San Bernardino, California, United States, county courthouses, California; FHL microfilm 1,290,189.
"United States Census, 1900," database with images, FamilySearch (https://familysearch.org/ark:/61903/1:1:MQMV-MJ1 : accessed 29 June 2020), Mary Annie Sabbot in household of Mike Sabbot, Precincts 5, 50, 44, 51-52 Salt Creek village, Pueblo, Colorado, United States; citing enumeration district (ED) 109, sheet 4B, family 71, NARA microfilm publication T623 (Washington, D.C.: National Archives and Records Administration, 1972.); FHL microfilm 1,240,128.
"United States Census, 1900," database with images, FamilySearch (https://familysearch.org/ark:/61903/1:1:M95M-LHX : accessed 10 July 2020), Mary Keil in household of Frederick Heil, Redlands Township Redlands city Ward 1, San Bernardino, California, United States; citing enumeration district (ED) 229, sheet 2B, family 27, NARA microfilm publication T623 (Washington, D.C.: National Archives and Records Administration, 1972.); FHL microfilm 1,240,097.
"United States Census, 1910," database with images, FamilySearch (https://familysearch.org/ark:/61903/1:1:MVL5-YJ5 : accessed 10 July 2020), Mary Heil in household of Frederic Heil, Redlands, San Bernardino, California, United States; citing enumeration district (ED) ED 108, sheet 3A, family 62, NARA microfilm publication T624 (Washington D.C.: National Archives and Records Administration, 1982), roll 94; FHL microfilm 1,374,107.
"United States Census, 1920," database with images, FamilySearch (https://familysearch.org/ark:/61903/1:1:MHW4-TZ7 : accessed 10 July 2020), Mary A Heil in household of Fred Heil, Jr, Redlands, San Bernardino, California, United States; citing ED 169, sheet 4B, line 58, family 103, NARA microfilm publication T625 (Washington D.C.: National Archives and Records Administration, 1992), roll 129; FHL microfilm 1,820,129.
"United States Census, 1930," database with images, FamilySearch (https://familysearch.org/ark:/61903/1:1:XC6C-KH7 : accessed 10 July 2020), Mary E Heil in household of Fred Heil Jr., Redlands, San Bernardino, California, United States; citing enumeration district (ED) ED 48, sheet 1A, line 20, family 8, NARA microfilm publication T626 (Washington D.C.: National Archives and Records Administration, 2002), roll 188; FHL microfilm 2,339,923.
"United States Census, 1940," database with images, FamilySearch (https://familysearch.org/ark:/61903/1:1:K941-B4H : 4 February 2020), Mary A Heil in household of Frederick Heil, Redlands, Redlands Judicial Township, San Bernardino, California, United States; citing enumeration district (ED) 36-76, sheet 5B, line 59, family 119, Sixteenth Census of the United States, 1940, NARA digital publication T627. Records of the Bureau of the Census, 1790 - 2007, RG 29. Washington, D.C.: National Archives and Records Administration, 2012, roll 290.