Agreed. With twenty months until the election, it seems really soon for candidates to be out campaigning. Hillary came out early to stop Obama, but the rest on their side were all testing the water to see if they could overcome Hillary.
Besides, Hillary may be the candidate for the left but even that is still up for grabs, IMHO. If Hillary has a Howard Dean moment in the future, she could very well find herself out of the running. I know I would not bet that Hillary will keep her cool for almost two years. I don't think she has that in her.