''This is from 19 years ago, and look how much we've come together since then. ''Now we're on super-fast broadband, and boom-boom, everything is done by internet. The pace of change ...''
The 67-year-old has extensive experience in the education sector, having taught at many different levels before becoming principal at Logan Park High School 18 years ago.
She trained at Christchurch Teachers College and began teaching English at Rutherford High School, in Auckland, in 1973.
Two years later, she went on maternity leave after having her first son, and then worked part-time at Henderson High School and Carrington Polytechnic (now Unitec Institute of Technology) part-time.
In 1977, she began teaching full-time again, at Papanui High School, in Christchurch.
A year later, she began her first stint at Logan Park High School.
But four years later, after the death of her first husband, she decided to take a teaching job at Blue Mountain College, to gain some experience in a rural school.
It was not until the mid-1980s that she returned to Logan Park High School, where she eventually became head of the English department, a house dean and the PPTA chairwoman.
In 1989, she took sabbatical to study women's history, women's literature and women in education, as a postgraduate student at the University of Otago.
In the same year, she also remarried, and in 1990, she took maternity leave again to have her second child.
''Then I decided to go for a job as a senior lecturer at the Dunedin College of Education, and I trained teachers for about eight years - primary, secondary, and would you believe it, early childhood teachers.''
She then became the deputy principal at Kaikorai Valley High School. But when the principal's job at Logan Park High School came up, she applied.
Mrs Johnson retires in July, but will not be walking out and not looking back.
She said the board of trustees was allowing her to take sabbatical during term 2, to write up a pupil achievement research programme that staff and pupils had been involved with during the past three years.
''Now is a good time to retire because I think the school is in very good heart, and I know the senior management team is fabulous. There's lots of talent there.''
She said it was important to step aside and let a younger, fresher generation take over.
''It's a very big job and you have to do it with energy, commitment, enthusiasm and a sense of calm, every day.''
Peter Hills will take over as acting principal from May 1, while the board of trustees conducts a search for a permanent principal.
Mr Johnson said she planned to act as a consultant for the school, to give help with anything the school needed.
She looked forward to being free to do whatever took her fancy. In the interim, she wanted more time with family and friends.
