Celebrating on Saturday in Oamaru, Mrs O’Brien said it was her early childhood on a farm at Hillend that set her up for a long and healthy life.
"If you’re brought up in the country you always have plenty of fresh vegetables and meat and milk and butter and everything like that," she said.
When she was 6 years old, she moved to Andersons Bay, in Dunedin.
She moved to North Otago when she married Thomas O’Brien.
The youngest of her eight children, Clint O’Brien (57), said when growing up on the family’s small drystock farm near Weston, his farmer mother always "looked out for the underdog" and was always able to see the positive in people and things — even if others might see them as damaged goods.
"She’s the sort of person where if you had a broken clock on the wall, it’d still be right two times a day," Mr O’Brien said.
"It doesn’t matter how worn out something was, or how broken down something was, there was always something positive about it.
"The same with people — broken down people who have had bad luck, she would always give them a hand. She’s always been charitable."
Mrs O’Brien officially became a centenarian on October 19, but yesterday, friends and family filled the Salvation Army Hall to wish her well.
Mrs O’Brien will not wait long for her next big bash — she said this year she was looking forward to her great-grand-daughter’s wedding.
Hazel O’Brien (23), who will marry Bryce Nicholson in Danseys Pass on November 26, agreed her great-grandmother had a positive outlook on life, so much so that well into her 90s Mrs O’Brien liked to bake for the "elderly" — despite the fact those receiving her goods were up to 20 years her junior.