And it was a bit of a surprise to her she made it to her 100th birthday yesterday, because she had never really wanted to live that long without her husband, Thomas.
"I was 34 years married, and 45 widowed. He was marvellous. He said to me, 'Get married again', but I couldn't. Nobody could take his place."
To celebrate her birthday, Mrs McMullan went for a short ride in a 1912 Model T Ford owned and driven by Dunedin man Rolly Bell, and organised by the staff at her rest-home.
She said she learned to drive in a Model T but never gained enough confidence to get her licence and spent the rest of her life being driven around by her husband and then her children.
Kathleen Sullivan Brown, known as Cassie, said she grew up in Naseby, the daughter of a gold miner and one of eight children.
She spent most of her childhood "running around the hills" near Naseby with her brothers, and had to walk two miles each day to and from school - a healthy, fit lifestyle she credited for her later longevity.
One of the other great loves of her life has also kept her sprightly - her love of babies.
She said that when she left school at 14, all she wanted to do was be a mother. "I was baby mad. I prayed for a baby. Of course, I thought all I had to do was go to the hospital and pick one up."
At 17 she met Thomas McMullan, an Irishman working in the area, who was invited to dinner at her house after Mass one night.
They were married a few years later and lived in Wedderburn for several years before moving to Dunedin. Mr McMullan was a steamroller driver for Dunedin City Transport and Mrs McMullan at one point ran the shop and post office in Macandrew Bay.
The couple had four children.
Mrs McMullan described all of her 11 grandchildren and 16 great-grandchildren as "lovely", and was pleased they all still seemed to like her, even though she sometimes had a "hard hand" with them when they were little.
She said she still loved babies even now, and people often brought their child to see her because they knew she loved to meet them.
A fierce knitter, she had to give up several years ago because of failing eyesight, but she still wore heels - something she had always done, even in the garden.
Mrs McMullan lived in her own place until she was 96, when she moved into Little Sisters of the Poor in Brockville.
Turning 100 had been quite the event, but she still had the capacity to surprise herself, she said.
She made her first-ever public speech to more than 100 family and friends who attended an afternoon tea on Sunday.
"It took me 100 years to do that and I still lay awake that night thinking how on earth I did it."
