Hi Patty,
I did a genealogy course some months ago and the most frequently asked question was about the 1901 and 1911 census of Ireland. Everybody wanted to know why their grandparents had advanced more than 10 years in age since the 1901 census?
The professional genealogist who ran the course said that we have to try and put ourselves in the shoes of our ancestors. Many people were uneducated. Very few had an actual birth cert, and absolutely nobody celebrated birthdays. It was difficult enough to make a living and feed children, so birthdays weren't even mentioned. As a result of this the old age pension came into being in Ireland in 1909, but old people didn't know what age they were and most had to go back to church records to find out what age they were. A baptismal cert was accepted as proof of age. So many people who might have been 65 or so in 1901 found that they were actually 80+ and such in the 1911 census. There were huge discrepencies with what age people thought they were and what age they actually were.
I would say this could be applying to your case here. Nobody had birth certs when immigrating and gave what age they thought they were.
I went on the irishfamilyhistoryfoundation website and gradually input your information. There are many cornelius o connors in ireland but I have only found one Cornelius O Connor whose father was Michael O Connor and mother named Johanna.
This person was born in 1887 and registered in the Co. Waterford site. When I scrolled down through the parishes, he was born in Abbeyside, which is smack in the middle of Dungarvan.
I feel that this is indeed your ancestor. You will need to get onto this website and go on the Co. Waterford genealogy section. You can join this site for free and trawl through many records and cross reference. You only pay to view a particular record and it costs approx €6 to view. You should take a look at this record.
Kind regards, Anne K Dennehy