This might be your grandmother?
"United States Census, 1940," database with images, FamilySearch (https://familysearch.org/ark:/61903/1:1:KWHY-QBX : accessed 7 October 2016), Gertrude M Cecil in household of Carl J Cecil, Ward 4, Galesburg, Galesburg Township, Knox, Illinois, United States; citing enumeration district (ED) 48-20, sheet 20B, family 511, 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.:
Carl J Cecil Head M 35 Kentucky
Gertrude M Cecil Wife F 27 Illinois
Margaret M Cecil Dau F 3 Illinois
Leon J Cecil Son M 2 Illinois
Stella Cecil Dau F 0 Illinois
The following records seem to be related by names and locations:
"Illinois, Cook County, Birth Certificates, 1871-1940," database, FamilySearch (https://familysearch.org/ark:/61903/1:1:Q2S8-L79N : 18 May 2016), May Gertrude Perry in entry for Joseph Leon Cecil, 19 Apr 1938; citing Chicago, Cook, Illinois, United States, reference/certificate 17955, Cook County Courthouse, Chicago; FHL microfilm .
Name Joseph Leon Cecil
Birth 19 Apr 1938 Chicago, Cook, Illinois
Registration 18 May 1938 Cook, Illinois
Father John Carl Cecil Birthplace: Kentucky Age 33
Mother May Gertrude Perry
Age 25 Birthplace: St Augustine Illinois
Certificate Number 17955
"United States Census, 1920," database with images, FamilySearch (https://familysearch.org/ark:/61903/1:1:MJ4L-Y17 : 14 December 2015), Gertrude M Perry in household of James H Perry, Saint Augustine, Knox, Illinois, United States; citing sheet 2A, NARA microfilm publication T625 (Washington D.C.: National Archives and Records Administration, n.d.); FHL microfilm 1,820,380.
James H Perry Head M 49 Illinois
Stella C Perry Wife F 39 Illinois
Bessie C Perry Dau F 16 Illinois
Gertrude M Perry Dau F 8 Illinois
Frances R Perry Dau F 5 Illinois
The link below, shows records of James H Perry and Estella/Stella Catherine Strickland, marriage, their parents names etc. Needs further confirmation: