[Rebecca]

You can play Pro Master without upgrading to Pro but make sure you don't accept cash. If you accept cash in 2013, you will have to upgrade to Pro in 2014. It doesn't matter what your rating is.

Now, if you want to play Pro in the Worlds in 2014......I would recommend that you play some tournaments as Pro Master so that you accumulate enough points for an invite to the Worlds 2014. Invitees get first dibs on registration. Or you can take your chances and hope that it doesn't fill.

As far as difference in the Pro and Am.......it's the title and you accept cash instead of scrip. And usually the registration fees are higher.