This was meant to be a comment, not an answer, but I don´t have enough reputation. Basically, I did a masters in maths (pure maths), then a masters is physics (qft), then a phd in maths (pure, algebraic geometry stuff). So, I had to grapple with the issue you are trying to solve. I think it will be hard to get a good answer since you don´t specify for what reason you want to learn QFT. Some comments then:
If you are going to work on things like Seiberg-Witten equations from a math perspective, then I suppose the book of Baez and Muniain called Gauge Fields, Knots and Gravity (mentioned by Bob Jones above) is great since you will not need to quantize things anyways.
If you actually want to get an understanding of the subject that includes the physics perspective (which is what I tried to do), then I suggest developing some physics background. So, I suggest reading the book of Sakurai in quantum mechanics (which, from my pure math background of the time, was a good book), together with books that are for the laymen: Feynman´s QED and Weinberg´s The discovery of subatomic particles. I used these books with Peskin and Schroeder´s An Introduction To Quantum Field Theory.
Actually, I tried to follow at the same time a more "mathematically precise" approach to QFT - but in the end I thought this was harder than the physics approach - because, I think, you end up spending an enourmous amount of time to get anywere, and risk the change of being burried in a pile of math formalism before being able to do simple computations.
A last comment. In my experience, it was great to talk to physicists (they tend to be more chatty and tell more stories about their subject than mathematicians). So, I believe that it is highly profitable to hang out around a group of physics students/professors while studying qft.
This post has been migrated from (A51.SE)