You have someone applying for an old age pension in 1916. He thinks he’s over 70 but doesn’t have a baptism certificate or other acceptable document to show his age. Obviously if he was 5 or over in the 1851 census, he would be 70 in 1916 and therefore eligible. So he claims to be born c 1846.
The form asked him to say where he was living in 1851, for the census look up clerk to check. He put down Miltown Row. So that’s his recollection of where he was living 65 years previously, when he was reportedly 5. Plenty of scope for error there. My guess is that he probably did live at Milltown Rd at some point in his life but it must have been later, as it was apparently not built in 1851. In the 1800s people in Ireland didn’t normally celebrate birthdays and often had little accurate idea of how old they were. Ages on censuses and other documents were often just guesses. In this case my suggestion is that he’s mistaken about where he was in 1851. Indeed he may not even have been born. Milltown Rd was where he lived some time later.
Alexander Irvine was born in 1863 in Antrim town and became a Minister living in the US. This extract from his book “The Chimney Corner revisited” perhaps explains why people often had to guess their ages:
“My mother kept a mental record of the twelve births. None of us ever knew, or cared to know, when we were born. When I heard of anybody in the more fortunate class celebrating a birthday I considered it a foolish imitation of the Queen’s birthday, which rankled in our little minds with 25th December or 12th July. In manhood there were times when I had to prove I was born somewhere, somewhen, and then it was that I discovered that I also had a birthday. The clerk of the parish informed me.”