Two years isnt uncommon, it's about average.
Brooklyn - i pitch quite a lot, and for similar stuff. Aside your pitch book, when you are at the meetings the tip i would give is to make it as visual as possible, whether thats bringing out storyboards, characters, concept art etc. Keep any talking simplified and use soundbytes, key points and be as concise as you can, ie - don't go on too much lol. I think if the people watching dig the look of the show and the basic concept you are half way there, obviously demonstrating it has appeal to their demographics and potential for licensing/merchandising , international sales etc is all going to add up in your favor.