In addition to what I learned through my parents, I had four good jazz resources in the generally suburban area where we lived:
A weekly AM radio big band/swing show
A community FM radio station that played jazz on weeknights Monday-Thursday
An NPR station that played jazz after 11; I would go to sleep with this.
Peaches Records, which had an extensive jazz LP section, including affordable twofers, and a massive cutout bin.
I was listening primarily to acoustic jazz in high school, but a friend had Bitches Brew, and we used to get high to it. At around this time, I picked up In a Silent Way, based on some things I read, and I thought it was simultaneously more interesting while also providing a good chill out vibe. To this day, I much prefer In a Silent Way to Bitches Brew.
Either way, I think it is a safe to say that Miles has served as a jazz entry point for more listeners than any other single jazz artist.