my case is interesting. I've always been a gamer, since my parents bought us the Odyssey 2 I played a lot. Then I got a CP/M PC with crappy games, and when I got in college I got myself a 'PC clone'. My first 'RPG' was Temple of Apshai, first time I had 'attributes' and progression in a game. Liked it, but then my world changed when I got Wizardry 1, it was the first game where seeing the sun coming up through the window caught me by surprise.
And then, not much later (a few months), I noticed a pamphlet at one of my university's restaurants that said "This Thursday at 1pm come to an Advanced Dungeons and Dragons tournament"… I only knew about that name from an Intellivision game with the same name (but nothing really to do with the actual AD&D), so I thought it would be a tournament of people playing Intellivision… I didn't go.
But my friend did go and he later explained to me about that awesome game, he even had a Player's Handbook that someone had lent him, and while my eyes browsed through the pages, my mind was lost in imagination. Then I joined his new AD&D group, and my life changed (and my grades too unfortunately).
So when I think of CRPGs now, my base is PnP Dungeons & Dragons, even though technically my first contact with CRPGs was before that.