Can anyway help me with finding more about my great grandfather, John Francis O'Shaughnessy?

Grandfather born 12/25, 1851. Information says he was not baptized until July 22 1858 in Askeaton County, Limerick. Woman from St. Mary's Church did not find anything. Odd that he was baptized so late. Census info also odd: says he immigrated in 1870 and 1873. Siblings, Patrick, James, Kathleen and another brother who went to Scotland; name unknown. Just discovered I used 1951, 1958, 1970 and 1973 in errore. Edited to show correction.