One would expect that the baptism date of a child would be on or most likely after the birth date. Not what you will find always in these records in Ireland after State Records began in 1864 and indeed up to the early 1900′s.
It was normal in that era that a Catholic child was baptised within a day or two of being born and indeed if the birth was early then the baptism may take place that day. It is not uncommon to find a significant difference between a birth date on the State Register and the Baptism date in the Church Baptism Register. The baptism date could predate the birth date on the State Record by several weeks. One notes in the State record that the birth was often registered several weeks after the stated birth date. I tend to take the baptism date as being the more reliable. The child, Timothy on http://bmdnotices.com/remembrance…/viewremembrance.aspx… has a baptism date of 23 Aug 1868 and a birth date on the State Register as 17 Oct 1868.
If you are beginning a research project to trace your family history, then one of the initial requirements is to document the facts you have from a particular point or generation. Begin with what you know of your parents and their siblings. Have you dates / locations of birth or marriage details?
Talk to older relatives or indeed neighbours of any ancestors you know about. Talking to the elderly people can give a great insight into establishing a framework to build upon. Using this framework you can progress to add locations, facts and dates as they become available.
From birth details of your parents you stand a great chance of getting a background on their parents (your grandparents) and siblings.
A word of caution, do NOT simply insert names, dates etc if you are unsure, instead WAIT and keep checking and researching. You are not in some kind of race; do your thorough research and be sure of your facts. We have a huge number of examples in family trees where even the dates of birth of parents are after the birth of their children. Don’t rush and check the information. Remember this is part of your legacy to family members, even not yet born.
The State or Civil records in Ireland are available from 1964 to date. See http://www.welfare.ie/en/Pages/Apply-for-Certificates.aspx
Roman Catholic Church records in some cases date back to the 1770′s or after while others like Kilmacabea Parish began in 1832. Indeed you will find too that several (maybe up to 10%) of births and marriages are not recorded. The Church of Ireland and Methodist Churches have records dating back a few hundred years. One problem in all Church records was the lack of information e.g. address, fathers name of bride or groom (great if we got a mothers name but that did not happen normally), age.
You may find it beneficial to visit some websites. Here are a few which are free and no login required to view data:-
www.familysearch.org which covers much of the world
www.irishgenealogy.ie and this covers part of Counties Cork, Kerry, Carlow and Dublin in Ireland
For the 32 Counties of Ireland there is the Census of 1901 and 1911 http://www.census.nationalarchives.ie/