If you simply can’t wait another week and a half to play Borderlands 2 then tough cookies, because you have to wait at least that long until you get to play the game still. However you can start planning how you want to level up your class of choice or even pick a certain class if you are still on the fence.
Today the Borderlands 2 website has been updated with an official skill tree calculator that will allow you to simulate your character’s ahead of time and learn about the various skills each one of them can employ on the field of battle. The calculator can be found here.