Is your great grandmother's name IDA MAE or IVA LEE?
The IDA MAE WHITMIRE that was born Feb. 18, 1903 and died July 1986 in Buna, Jasper Co., Texas was the wife of JESSE JAMES WHITMIRE and her maiden name was "DAY". I think we can eliminate this person as being your great grandmother. (I found this on the findagrave.com website)
You mentioned that your great grandmother lived in Lake Worth Texas for many years - Lake Worth is in Tarrant Co., Texas. Perhaps that is where she died.
Perhaps your aunt can give you more detailed information on your great grandmother. Are you sure about her maiden name being "HENRY" and was she married just once - to THOMAS WHITMIRE?
I will keep searching - Sincerely, Melinda