I looked at civil birth records from 1897-1904 for a Nora Geoghegan. I located one possible lead--- a Hanora Gahagan from Doon Co. Tipperary. Father was William and mother was Mary Brown.
See third record from the bottom. https://civilrecords.irishgenealogy.ie/churchrecords/images/birth_return...
Lismore would be in Co. Waterford and where Doon is located is not far from Co. Waterford.
You would need the mother's name for Nora to confirm the record above. Do you know the names of any siblings to Nora?
I believe this is the 1911 census record for the family related to the birth record.