As of 2018, I have been testing software for thirty years. I never really intended to.
My degree was in mathematics, and I did not know where to go with that. But I had been working part time during college at a local health insurance company, so naturally I checked to see whether they had any jobs I could apply for… and they had something called “the model office.” They had bought a big software package to be customized and installed, and my business knowledge would apply, so I got the job. There was no training for it, really, but they gave me a copy of Boris Beizer’s Software Testing Techniques, IIRC. I had to figure out how to devise and document the tests, how to store them… everything was on paper at first. Eventually we used Paradox (does anybody remember that?) and Lotus 1 2 3.
And now I’m on a semi-agile team. I’ve been meaning to learn test automation for about, I don’t know, 15 years? But nobody I’ve worked for wants to spend the time/money to do it, so… I still don’t know it.