My first dev project was back in the 80's. I might have been around 10, I think.

My friend and I had been tinkering around Shoot'em up construction kit for a while, plus we'd been quite inspired by all the cracktros, intros and whatnot was popular back then (piracy was huge, at least on the C64 platform - I don't think I ever saw an original game until my parents bought an Amstrad CPC).

Anyway, we were inspired. We didn't know how to code except some basic BASIC (ba-dum-tsj). We borrowed a book from the library on how to code an assembler for the C64 in BASIC, and coded for days. I eventually lost interest, but my buddy did actually complete it.