Yup. I was able to teach my kids how to open and use QuickBASIC when they were little in the 90s. Now I'm not sure what approach I would use to teach a child actual coding (vs. moving stupid blocks around on a screen that PR flaks call "coding").
To answer the OP question (and agree with the GP of this reply), it was absolutely all self-taught, as were the additional languages I've picked up over the last 40 years.
Started with the TRS-80 in Radio Shack. I checked out "Basic BASIC" from the library and took it over to the mall every day after school, typing in all the exercises.
When they threw me out of Radio Shack, I moved over to Foley's where they had the shiny new Commodore PET on display. After I finished Basic BASIC, I moved on to Dave Ahl's BASIC Computer Games. I got to know the evening shift salesgeek pretty well and he let me spend all my time hogging the display computer. He would sometimes show me some cool hack and challenge me to figure out how he did it, such as POKEing directly into video memory for fast animation. I eventually bought my first computer* from that guy.
All of which is to say: Suck it, Radio Shack.
*The PET. Although Foley's also had an Altair on display, it was more expensive and all the blinkenlights frightened and confused me.