Self was born in Hamilton, Montana, USA, on 14 August 1909 (claimed 17 August), as the youngest of nine children born to parents Walter Leonard Chesnutt (1855–1933) and Susan Alvina Campbell (1869–1949). Her siblings were: Lessie Marie Harris (1891–1953), Grace Willie Jones (1892–1986), Booth Chesnutt (1893–1963), Eunice Frances Donaldson (1895–1967), Ella Irene Howard (1898–1967), Walter Chesnutt (1900–1965), and Joseph Chesnutt (1906–2007). She was raised in the Bitterroot Valley, where she attended a school in Grantsdale. Throughout the 1918 flu pandemic, she and her brother Joseph would visit neighbors and run errands. At the age of 12, she relocated to Missoula to reside with her sister Lessie and began attending a school in the area.

On 28 November 1928, she married Bernard George Reesman (1908–1972). The couple had two children: Shirley Gunter and Kenneth Reesman. They divorced on 1 January 1946.

In May 1946, she married Thomas Edison Mongar (1912–1969). They were married for 23 years before her husband died in an airplane accident working for Montana Power Company.

Her third and last husband was Kenneth Ray Self (1913–2001), whom she married on 20 May 1972. Over the span of more than 20 years, the couple traveled to Arizona, Florida, and Alaska. Her husband passed away from cancer in July 2001. In October of the same year, she moved in with her granddaughter, Diane Gunter.

On her 100th birthday, Self took her first ride on a Harley-Davidson motorcycle. Her brother Joseph passed away in 2007 at the age of 101. When she was around 108 years old, she embarked on a camping trip with her daughter at Lake Como in the Bitterroot Valley. As of her 109th birthday, she had six grandchildren, 18 great-grandchildren and two great-greatgrandchildren (with another on the way). It was reported that, apart from her eyesight and hearing, she was in excellent health at that time.

Self passed away in Missoula, Montana, USA, on 29 July 2021, at the age of 111 years, 349 days.