No idea. Actually, no idea how I got started liking SF at all, now I think about it, and whether TV or books came first. Mind you, I have trouble remembering last week, so maybe that's not surprising.
I remember a BBC 2 sci fi 'festival' and I remember all sorts of classics like Them!, The Day The Earth Stood Still, This Island Earth and more. I remember being disappointed we weren't going to make it home from my grandparents to see Robinson Crusoe on Mars. Things is, though I know I was watching those because I already liked SF. Dr Who, Space 1999, UFO, Thunderbirds, Star Trek (now known as TOS) and more were all in there early in the mix. I know I was very SF biased from a very early age... but don't know how that came about.
Book-wise, there was Hitchikers, and Nicholas Fisk's Splatterbang, and some Andre Norton. Lord of the Rings (ok ok, I know, that's SFantasy not fiction)... but again, the first one that made me go "This is it! SF is my thing!" I dunno.