I search the IFHF's online database at ROOTSIRELAND.IE. It has abt 20 M church, civil, census, etc records for MOST Irish counties. Records before 1863 are increasingly sparse - almost non-existant before 1800.
For Mary McCafferty B 1824 +/- 1 yr, somewhere in Ireland, with a father forenamed John, and mother Sarah, I found 0 records.
For a Mary McCafferty and James McCann marriage 1845 +/- 4 yrs, somewhere in Ireland, I found 0 records.