A January 1821 Birth Date is consistent/common sense with a baptism date of Jan 18th.
url https://familysearch.org/ark:/61903/1:1:FRWK-R8Z Name: Daniel Sullivan Event Type: Christening Event Date: 18 Jan 1821 Event Place: Killarney, County Kerry, Ireland Event Place (Original): Roman Catholic Church, Killarney, Kerry, Ireland Gender: Male Father's Name: Dl. Sullivan Mother's Name: Ellen Connor Citation: "Ireland Births and Baptisms, 1620-1881", database, FamilySearch (https://familysearch.org/ark:/61903/1:1:FRWK-R8Z : 5 February 2020), Daniel Sullivan, 1821.
Have you taken a DNA test? If so, login to add it. If not, see our friends at Ancestry DNA.
Daniel is 31 degrees from Emeril Lagasse, 32 degrees from Nigella Lawson, 34 degrees from Maggie Beer, 56 degrees from Mary Hunnings, 37 degrees from Joop Braakhekke, 36 degrees from Michael Chow, 31 degrees from Ree Drummond, 34 degrees from Paul Hollywood, 31 degrees from Matty Matheson, 34 degrees from Martha Stewart, 32 degrees from Danny Trejo and 37 degrees from Molly Yeh on our single family tree. Login to find your connection.