1880 U.S. Census lists "Fanny W Custer" as 63 years old.
"United States Census, 1880," FamilySearch, Fanny W. Custer in household of Solomon Custer, Dublin, Jackson Township, Wayne, Indiana, United States; citing enumeration district, sheet, NARA microfilm publication T9 (Washington, D.C.: National Archives and Records Administration, n.d.), FHL microfilm
[1880 U.S. Census lists "Fanny W Custer" as 63 years old.]
If Fanny was born in September (as one obituary claims), then she would put her birthyear at 1816.
However, if she was born in 1817 (as the same obituary claims), then she would have been turning 63 in a few months.