"It's a long way to Tipperary," the mother of five sang into the microphone, harkening the popular 1912 anthem sung by soldiers on their way to the Western Front during the summer of 1914.
"I'm kinda flat," she says, apologetically, to the singer and pianist who serenaded Jefferis and other residents of Versa Care Rexdale at her party.
A caregiver lifts the petite, feisty white-haired woman to her feet for a dance to Dean Martin's 1953 hit, That's Amore. But it was the familiar lyrics of Que Cera Cera that got the room of residents roused.
So, what's the secret to long life?
Hard work. "I worked hard all my life until I came in here. And I never got paid for it," she said.
Charlotte Marion Alethea Yule was born on Feb. 3, 1903 in Toronto.
At four, she went to live with her aunt Alley and Uncle John in Nelson, Ont. She married Edwin Roy Jefferis, and moved to a small farm in Waubaushene, Ont. where the couple had five children.
"Money was scarce, but were they good kids," she said.
In Waubaushene, she attended the local United Church, and was an active member of United Church Women. She joined the Women's Institute, serving as president and treasurer, and participating in sending parcels to troops overseas during the Second World War.
In her day, she loved to dance the waltz, two-step and the foxtrot.
Jefferis remained in her house in Waubaushene until age 97, when she moved in with her daughters. Later, she moved to the Versa Care retirement home on Humber College Boulevard.
Today, she has two stepdaughters, 14 grandchildren, 17 great-grandchildren and 10 great, great-grandchildren.
The future, she says, doesn't frighten her.
"One never knows from one day to another what's going to happen," she said. "Only One knows and that's God in heaven."