I don't know that I was ever at stage 0, but I was definately at stage 1. Never had to pass through stage 2, because all my uni and linux experience comes from the university mathematics labs, so it was already installed. =]
I think we all go through atleast bits of stage 4 at some point in our lives, I know I have multiple times.
I'm proud to say that once I have a steady job I'll finally manage to reach stage 5. I don't know how much further I'll get though.