I’m still amazed that the first dozen programs I ever wrote back in 1963 for an IBM 7090 (or 7094) ran first time. (They were trivial programs). I’m also still pissed that I never got to debug the 13th, in FAP (Fortran Assembly Program), which had a minor syntax error – a comma instead of a period, or vice versa. NASA had just launched a weather satellite, which monopolized computer time, leaving zero minutes for high school students.

I started in 1966 with Fortran II on CDC 3500. Later I spent quality time on the IBM 1800 which has the same instruction set as the 1620.

Nuts, I was going to post that FORTRAN (IV) was my first programming language, but that was in 1969. So you have me beat!