For me, this proved to be a somewhat a tricky question. I first asked myself when I first realized that I had fallen in love with music. Then, I asked myself when I first started to really care about the sound quality of the equipment used to play the music I liked.
I started buying my own 45s when I was around 7 or 8, after using my aunt's portable tabletop 45 record player for a few years. The first 45 that I bought was "The Battle of New Orleans" by Johnny Horton. I was around 7 or 8 years old then and happened to be at my grandmother's house. I must have played that 45 ten times in a row, if not more. My grandmother never said a word; never asked me to give it rest! God Bless her! That kicked off my 45 record collection. Wish I still had those things!
Sometime around 1960 or so, my parents bought a Grundig stereo console. It had a turntable, AM and shortwave radio built into it, as well as speakers or maybe it was just a single large speaker. That's when I began my LP collection.
Sometime in the mid 60s I became much more aware or concerned with the sound quality that the equipment I was using could deliver. That's when I bought a stereo in a box type thing that came with 2 small bookshelf speakers and an amplifier with built-in 8-track tape player. Can't remember the name of that thing. However, my friends and I thought it sounded pretty good. That kicked off my 8-track tape collection. Soon thereafter, I bought a Craig reel-to-reel and started recording music from AM radio stations and, later, from FM when that became more popular. I'd have to say that was the spark that started the audiophile fire.
In the late 60s, one of my high school musician friends wanted me to listen to a new stereo system that he had just purchased. Can't remember the model numbers but it was a Sansui integrated amp, Thorens TT and a pair of bookshelf speakers. I think the TT cart was a Shure. He loved Chicago. So, we played their new album and the sound from that system just blew me away! I have to say that's when the audiophile bug started, for me.
In 1972, I had finally saved enough money to purchase what I consider to be my first entry-level audiophile quality two-channel stereo system. This very same friend, much more knowledgeable about stereo equipment than I at the time, took me to Tech HiFi in Cambridge, MA. That was a kid in the candy store moment for me! After spending money that I really should have devoted to college expenses, I walked out with a Sansui 2000X receiver, Phillips 212 TT equipped with a Shure cart and a pair of Studiocraft speakers that I eventually upgraded to Ohm C a year later. The rest, as they say, is more history.