ISO F born 1958-60, IA or NE

I'm looking for my aunt (father's sister) who was likely born in Western Iowa or possibly over the state line in Nebraska. All we know is that she is older than my uncle (49), and was female. My grandmother had my uncle fairly young, so we estimate her DOB to be in 1958-60. I would appreciate any pointers anyone might have in trying to find her. The family just found out she exists. My grandmother said she left "all doors open" for the girl.