Marie,
In case I misunderstood your last post, the civil registration which began in 1864 was for people of ALL denominations. The civil "parish" actually encompasses many church parishes, so always look at records in the surrounding locality. As you say 1869 is quite late if she was married in 1873, so I would be looking at much earlier dates.
Most people who emigrated were illiterate and undocumented. They didn't know how to spell their names and hadn't a clue as to what age they were. At the port of arrival their names were recorded phonetically, their ages were only guessed, and this is the information that followed them for the rest of their lives.
The proof of this occured in 1909 when the old age pension was introduced into ireland. People had to prove their ages and were forced to go through baptismal records to establish when they were born. That is why there is such HUGE discrepancies between ages in the 1901 census and the 1911 census of Ireland. Dates were found to be out by as much as twenty years in some cases.
Hope this is of some help to you,
anne