Mine was Harry Potter back around... 2000 or so? I stumbled across fanfiction by accident and woops, never turned back. :3 I'm also an old veteran of the Ron/Hermione vs Harry/Hermione ship wars and find it more than a little exhausting to wade through wank about Star Wars ships these days. (Maybe I'm just too much of a fandom granny to want to put up with that element anymore.)
Re: First Fandoms?