My introduction to the fundamentalist world began in earnest in my late teens and early twenties via Christian radio in NYC and NJ. I was listening to radio on a daily basis, since we didn't have a TV at the time being that we were pretty much dirt poor and always moving from apartment to apartment, generally one step ahead of being evicted. So while I enjoyed listening to music as much as any other teen, I also really enjoyed talk shows about public events, whether from a liberal or conservative perspective politically, or from different religious perspectives. I would listen to various Christian programs on the radio, but I'd also listen to some of the Jewish radio programming in NYC. At one point in my teens I considered converting to Judaism, since I found their ethical center to be very compelling to me morally. But I had been raised in a non-church-going but still officially Christian family, and so I was exposed from early childhood on to the bible and a little bit of religious writings, but not much else.
My earliest exposure to explicitly Christian preaching/teaching was through the Billy Graham Crusades on TV, which my mom always had me watch as a child. I didn't mind though, since his message was always delivered in a simple enough way that even I, a small child, could understand the basics of what it meant to be a Christian. I know that this was the case because at that time, when I was around six or seven years old, my parents had already split up and I saw my father Herbert only on the weekends when he had visitation rights. On one of those weekends we went for a walk down a wooded street a few blocks from our house and somehow the topic of Jesus came up. My father, who at that time lost the faith he was raised with, which had been a combination of Baptist (his father) and Lutheran (his mother), essentially told me that while Jesus was a good teacher, that's basically all he was. And I remember telling him no, that Jesus was much more than just a "good" teacher, that, in fact, he claimed to be much more and that he was actually God in the flesh. Now obviously I didn't really know what that meant in detail, since I was after all still a small child, but I had a true childlike faith in Jesus.
I also recall watching on a regular basis the wonderful Catholic program called Christopher Closeup hosted by the wonderfully gentle Father John Catoir, and each episode, which always aired early Sunday mornings, would offer up a morality play of sorts and would give dramatic presentations of difficult moral/ethical situations. The motto of The Christophers was "It's better to light one candle than to curse the darkness" and that has always stuck with me even to this day.