Now she has planned to undertake a one-year Masters degree looking at the role of public art in Auckland and its relationship to the city's ethnic diversity.
She's one of the few "older students" to continue through to the Masters level.
Ms Keats said keeping intellectually active had been very important for her mental health.
While she is no longer driving, the Freeman's Bay resident has been using the bus and trains to get around the city and see the various displays of public art.
"It's great. I've been able to go on the train to places like South Auckland, which I really like, and it not only has fantastic public art - especially murals - but good coffee as well."
Ms Keat originally trained as a teacher as she was "expected to fill in time before finding a nice man and getting married".
She found a nice man, married and had three children.
But after they had grown up she decided to start taking courses in art history at the university's Centre for Continuing Education.
In 2003, at the age of 71, a tutor encouraged her to do a degree course.
She took her first exam and was "hooked".
"I discovered I liked doing the research, it was like a treasure hunt."
Ms Keat took eight years to complete her Bachelor's degree, doing one paper per semester and attending summer school.
She has taken four years to complete the post-graduate diploma.
Ms Keat didn't think her age had made it harder.
"By this stage you've got used to it ... I'm fortunate to be in good health."
