To be honest, if it werent for WWII, chances are I wouldn't exist at this moment (long story about by grandparents), but, if i were to guarantee that the universe would not implode, and that there would be a world for me to time travel back to, I'd risk my birth so millions upon millions of people could potentially be spared a horrible death.
Now, to bring something up that hasn't been thought of, the OP stated that you would be snapped back to the present day after the job was completed. That isn't to say I wouldn't be able to kill Himmler, Goering, etc. first - Hitler's right-hand men who would take over as leader of the Nazi party after his death.