There is an Edna Marion Smith in the Minnesota birth index, date of birth December 5, 1903, mother's maiden name Betz.She was born in Carlton County. The index does not list parents first names.
Do you know where Edna and Earl Fishback married? Did she move to another state prior to her marriage? Do you know any of her siblings names? That may help locate her in the census, since her name is common.