Well, a typical order might be QM, relativistic QM, and then QFT. But obviously you don't need everything from QM for QFT, just as you don't need everything from relativistic QM for QFT. For example you don't need to solve the hydrogen atom in QM to do QFT, or any detailed scattering calculations in QM for that matter.
I'd just dive into QFT with an easier book like Mandl and Shaw, just to get you going, keeping in mind that later on you'll read a proper book on QFT which will show you how undetailed the easier book was.
I actually thought Zee's book was for people who already knew a bit of QFT. I can't imagine reading that without having done a bit of QFT. That derivation of the Weinberg-Coleman potential in the chapter on effective potentials, without using Feynman diagrams (!), seem to me a bit advanced.
O and I imagine a bit of knowledge of classical field theory, some CFT - lagrangians and stuff - would help in QFT.