Mrs Willson, who lives at Ranui Home and has multiple sclerosis, rides her mobility scooter over the road to St Gerard's School every weekday.
"I tootle across as soon as [staff at Ranui] manage to get me up.:
She is considered a valued member of the staff by both adults and children.
It is Mrs Willson's job to help children read by teaching them letter sounds and the alphabet.
"I just love the kids and the teachers,'' she said.
"He came and told [the staff] that I might be interested in coming over.''
That was two years ago.
"I came over for a day and from then on I just carried on.''
She said it was the pleasure of seeing children achieve, which she enjoyed most about her role.
However, it was not all plain sailing, she said.
"It is a struggle in the school holidays.
"I hate school holidays,'' she said. "I have to try and find something else to do.''
Mrs Willson was a teacher at Balclutha Primary School before moving to Central Otago.
Her experience and desire to keep teaching was admired by the staff at St Gerard's School, including teacher Chris Beilby.
"It's fabulous because you know all the kids are getting all the mileage.
"We just appreciate it so much and the kids' can't do enough for you,'' she told Mrs Willson.
In return, the children get another opportunity to read.
"It's fabulous,'' Mrs Beilby said.