Maureen there are a hell of a lot of Kate Regans but to choose one there is a Kate Reagan baptised in 1827 on 5th May 1827 in the parish of DRIMOLEAGUE, parents are CORNS REAGAN Mother JOAN CANTY, both spellings of Regan are in use. The site is free and click on Church records and select Cork, not all counties have their records on here yet. https://www.irishgenealogy.ie/en/ The civil records for all only started in 1864.
You may be able to find the actual entry here https://registers.nli.ie/parishes/0046 You can only search by Month and Year, the only reason for picking this one is the fathers name but it is also possible his brother called a daughter Kate etc. Unfortunately at this remove Irish records are church reliant and without more information it is nigh impossible to be totally confident.