There is the theory that Hitler was a reactionary, 'non-interventionist' dictator, and so the Nuremberg Laws and the Final Solution were largely due to pressure from Nazi supporters and his peers. I'll let you read on the theory itself as you can talk about all kinds of supporting evidence etc! There is no doubt that Hitler was of course anti-Semitic to the bone, and he would've started with his extermination at some point. This anti-Semitism was one of his pledges- winning support from the electorate and the right won't elite, and he was feeling the pressure to act on his promises. The Nuremberg Laws can be a prime example here- his peers and his supporters were crying out for another chance to hit the Jews (the last large part was the Kristallnacht that wasn't so successful) and so at the last minute (the night before) he switched his speech at Nuremberg from Foreign Policy in Abyssinia to announcing new legislation, thus being dubbed the 'Nuremberg laws'. So the short answer is that Hitler could not afford to put off his efforts until after the war, because there was still a thirst for anti-Semitism around him, and should they have started to lose faith in because of him failing to act, he would've been in trouble.