Whoa, that is so much bigger than all of mine together! Good job keeping it going. I had a regular cactus from "indoor plants" a few years later than yours that I kept going for probably 25 years. Eventually it rotten toward the bottom and some little wildlife kept eating it when I had it outside in the summer.
My instructor was Bob B-something. And BTW, I have more than a dozen African violets that came from DD and her then-boyfriend (now husband) when they took indoor plants as hort majors. Those plants are a little more temperamental.
My grandpa's hired man kept African violets as a hobby he had some grow lights in the porch of his house, he also had a Venus Flytrap. He was really quite the horticulture guy. Thanks for bringing back some good memories that I hadn't thought of in a long time.