I think the first one I installed was Debian back in '97 when I was 12. I think my dad helped a bunch, but I can't really remember stuff from back then very well.
My initial thought was that it was gentoo which I used as my principal OS for close to ten years. I don't know how many times I reinstalled, but enough that I basically had it by memory. Taught me to keep my home dir on a separate partition.
These days I mostly live in windows because AutoCAD is a part of my professional life, but I dual boot popos on weekends. Unless kernel updates break my displaylink docking station...
I used to have a 1/4" nut that missed the threading process. I had it on my keychain to remind me that even if something is done millions of times without error, sometimes mistakes can happen.
Lost it when my backpack was stolen.