I knew wrestling was fake/predetermined as a 12-year-old kid watching RAW every week in 1993 and it had absolutely no bearing on my enjoyment of the product. So that's never been an issue for me.
The biggest eye opener was when I got on AOL around mid '96, shortly after the Hall/Nash invasion stuff in WCW. At that point, I was reading for the first time about future storylines, wrestlers possibly jumping promotions, etc, and just thought it was fascinating. My favorite site was called "Micasa Wrestling News" which was mostly accurate news taken from the Observer 900 line.
The story that really captured my interest, though, was Bret Hart's negotiations with WWF and WCW that Fall. It sounded like he was leaving for the huge offer WCW had put on the table, so as a WWF fan, I was ecstatic when he chose to re-sign.
A few months later, after hearing the Observer pimped so much, I decided to subscribe and was absolutely hooked. So yeah, learning about the insider stuff really made me a much bigger fan.