My first introductions to programming was in Garry's mod.
There'e a mod called wiremod, which added logic gates, buttons, and other entities that manipulated the game with input/output. And on top of that a little scripting language they called Expression 2.

Me and some friends would code stupid things in Expression all day to use in the game.
I wasn't too good at it, but I had fun. Shortly after I started going to a high school with a computer science focus, and had 2 years of proper education in C#.