Full life for a century
Last year she moved into Tainui Village but she's not slowing down. Every day she goes for a more-than-leisurely walk, unaided by walker or stick, around Westown. In fact, one of the only impairments she has is hearing loss, requiring hearing aids.
And she's willing to share her secret to longevity: "If you take a little nutmeg regularly it keeps your glands functioning all over your body and gives you an effect of general good health," she says. "You must only have a shake. Not too much. Two shakes might overstimulate you."
Mrs Carroll has some amazing stories to tell. In her late teens, while living in Napier, the earthquake struck in 1931.
"In the front doorway I could look over the port of Napier and what was then the inner harbour had a lovely white bridge over it. Before my eyes the bridge just fell apart and land came up and water went back. That was the port of Napier, and now it's the airport. "
After training as a nurse in New Plymouth she graduated with the Top Nurse of Dominion honour and began training in maternity nursing at Masterton.
Biddy headed to England on the last ship from New Zealand before the coronation of George VI in 1937, a voyage that took six weeks.
On board she met her future husband, John Carroll, who later became a Merchant Navy officer. In England Biddy worked as a nurse at hospitals and maternity hospitals, and as a private nurse.
With the outbreak of war Biddy and John married and days later the pair went to South Wales so he could rejoin his ship. "The bombing was pretty horrific then," she says. "Every time the ship left the port the Germans came in and dropped mines so they couldn't get out. This went on for about four days and so we'd say goodbye in the morning not expecting to meet again. It was sheer hell."
Eventually there was a voyage he didn't come back from.
Biddy moved in with family but continued working as a nurse, despite the air raids nearby, as she waited for news of her husband. When it came it was grim.
"A German raider had caught them and stopped the ship, gave them time to gather a few bits, get into the lifeboats and they blew up the ship."
The crew was eventually taken to a prisoner of war camp somewhere in the lowlands of occupied territory – this was the only detail Biddy was sketchy on during the whole interview. Thereafter the news stopped. No-one knew if the crew had survived. Biddy's husband managed to barter with cigarettes, camp currency, for a message to be sent to Biddy.
"At the end of six months I was the first person to know that there were survivors and I was able to ring the shipping office in London and tell them this news. It was quite something. It amounted to 400-500 men from that ship and others."
Biddy was separated from her husband for three years before his freedom was negotiated.
Biddy and John had two children, a son and a daughter. They now have three grandchildren and three great-grandchildren.
Having lived through so many major events she wanted to impart some of her wisdom: "As opportunities come, take them. But don't expect other people to help you get used to them. You've got to do it. It's not always going to be pleasant," she says.
"If you take on a new job give it a good go but if it doesn't seem to be functioning for you don't be afraid to say you've made a mistake."
She thinks her longevity is in part due to her genes. Her parents both died in their 90s.