BCX Basic
bcxbasiccoders.com
bcxbasiccoders.com
I don't think it helped me much, in retrospect. It limited what I could create (programs were slow and limited in many capabilities) and it did not teach me a good programming style.
I wish I learned Pascal, SML or even C instead at that time. I just did not have access to compilers for those languages back then (it was on MSX hardware, a pre-PC).
If I remember correctly, 40 years later, I got run-length encoded monochrome image compression and decompression working in C, and a Conway's Game of Life with editor in Pascal, working using them.