She was ''a bit scared'' of Year 7-8s at first, the only age group she hadn't taught.
''But they're the icing on the cake really. Everyone else has done a lot of groundwork, it's like a finishing school getting them ready for the transition to high school.''
Lange's sights were, however, always set far beyond the kids' next year. A sign in her classroom read: 'In this room we are preparing ourselves for our first job interview after we leave high school.'
''I wanted them to have a sense of why I was getting them to speak properly and self-manage. They're not just preparing for high school," she said.
Highlights of her 30 years at Ōpua were many, including seeing her students go to high school, fearful on the first day but quickly gaining confidence and thriving; quiet girls turning into ''magnificent young women'' in Year 8; or watching as boys who'd always struggled with maths suddenly master angles because they wanted to build a life-size coffin for Halloween.
''I wouldn't have got anywhere if I'd sat them down and taught them about angles. They succeeded because it was what they wanted to do. It's finding the kids' interests and letting them go with it. That's the difference between teaching now and 58 years ago," she said.
The biggest highlight, however, was inspired by the TV show 'Dancing with the Stars.'
When the show started about 12 years ago the school brought in a volunteer tutor from Russell to teach ballroom dancing to Year 5-8 students. Every year since then the school had held a highly-anticipated end-of-year ball at the Copthorne, with a formal dinner for the children and an hour-long ballroom dancing presentation to the parents, teaching etiquette and social skills few of the children had experienced before.
Lange's explanation for why she taught for so long is simple: ''I kept not stopping.''
''This is like my extended family, you get used to each other. There's something really special about this place. It's a small school, you know everybody and you know their families, and we have a very long-serving staff. It's collegial, we all back each other up.''
She only stepped down when she realised she couldn't keep up with the demands of the job any more.
Lange grew up in South Auckland with a twin brother, a younger sister, and an older brother named David, who readers may be familiar with.
Having such a famous sibling could be annoying - ''I'm a person on my own, I don't need to stand on anyone else's laurels'' - but when the Tomorrow's Schools reforms were introduced it gave her a chance to have regular debates with the then Minister of Education.
Concerns she raised with her brother included school boards and the ERO (Education Review Office) system.
''I never won an argument with him, but I still think I'm right,'' she said.
One of the ''bureaucratic highlights'' of her career was a battle over a deeply flawed ERO report in 2014. It was awful at the time, but the school stood its ground and the report was eventually thrown out, she said.
Meanwhile, sitting around idly is not Lange's forte, so she finds herself ''getting a bit fidgety'' in retirement. She is, however, able to devote more time to music again. She was heavily involved in musical theatre when she lived in Auckland and taught generations of children recorder and ukulele.
She has just discovered the singing for fun group at U3A (University of the Third Age), which was in need of pianist, and she is able to put her classical training back into practice when she plays the organ at a Paihia church.
Ōpua School principal Simon Gowan said Lange's commitment to teaching over the years was second to none.
''She's a natural teacher. It's immeasurable how many children she has positively affected during her career. Many of them keep in contact with us, and remind us that she made a such a difference to their lives. She's irreplaceable.''