That will be hard when her four children, 12 grandkids and "27 and a-half great-grand babies" gather together to celebrate their matriarch’s milestone tomorrow.
"I’m not the sort of person who likes attention.
"It’ll be wonderful to see the whole family, but I’ll be just as glad when the celebrations are all done," Mrs Collie said.
It is no surprise she shuns the limelight.
As the third child from a family of six, she was raised in Otautau at a time "when there was too much to do on the farm to get caught up with oneself".
Mrs Collie was born Mabel Christina Froude on June 30, 1924.
She called herself her "dad’s land girl" because of all the work she did on the family farm at Pukemaori in western Southland.
"I was very strong and just brought up that way," she said.
Returning to the farm after finishing primary school at standard 6 did not bother her.
She embraced her farm life and dealt with the sheep, pigs, cows and driving the horses to plough the land.
When World War 2 broke out, she joined the voluntary aids division, studying first aid, hygiene and sanitation and home nursing, "in case the casualties of war returned to New Zealand needing medical help", she said.
She married her air force man Bruce Collie on July 11, 1945.
They had met as teenagers playing for rival tennis clubs.
She did not realise he "had his eye on her" back then.
Mrs Collie used her farming experience to join the women’s division of what was then Federated Farmers.
Connecting with other rural women to support each other and provide assistance to farming families enabled her to get involved with the community.
"Back then women weren’t given the recognition they deserved so it was good to be part of something where we could lift each other up," she said.
Raising a sports-mad family kept her busy and taking the children on camping trips to Wānaka was a highlight.
Her love for the outdoors continued with her and Bruce starting up a fly-fishing guide business in Wānaka in 1980. Winning a golf club championship at the age of 85, despite being on the mend from a torn tendon in her upper arm, did not slow her down.
Doing plenty of exercise and eating your veges was the secret to her longevity, Mrs Collie said.
"Get out and mix with each other, be competitive and enjoy your family. That is what makes a happy life.
"I think I’ll be going a while yet," she said.
