You don’t say what denomination Mary McKinlay was but the only church in the Ramoan area with any baptism records for around 1827 is Ballycastle Presbyterian. Theirs start in 1829. So, if Presbyterian, she might just be in that if her year of birth is uncertain. There are dozens of McKinlay/McKinla households in the 1803 agricultural census for that area, and 4 in Ramoan. Do you know what Mary’s townland was?