I started as a teenager as well. I was given three jazz LPs by a Peace Corps volunteer that my Dad was the Director of when we were living in Swaziland (Eswatini now). When my Dad was back in DC briefly I had him pick up a few LPs for me with my "allowance" dollars. Locally in one of the shops I found a few LPs to buy, notably the first Chicago and the second Blood, Sweat and Tears.
Then when we returned to the US I found "Filles De Kilamanjaro," "In A Silent Way" and "Bitches Brew" in the library and i a few months I had found my own copies of these. . . and my record buying began and continued pretty much into the early 'eighties. At that time I was buying cassettes and cds and sold some of my best LPs to a shop and to a few individuals who made me what seemed crazy offers. I concentrated on cds going forward, but was always buying an LP here or there that was not on cd.