If we would have had the 262 at our disposal - even with all the delays - if we could have had in '44, ah, let's say three hundred operational, that day we could have stopped the American daytime bombing offensive, that's for sure.
It is true to say that the first kill can influence the whole future career of a fighter pilot. Many to whom the first victory over the opponent has been long denied either by unfortunate circumstances or by bad luck can suffer from frustration or develop complexes they may never rid themselves of again.
Never abandon the possibility of attack. Attack even from a position of inferiority, to disrupt the enemy's plans. This often results in improving one's own position.
During the Battle of Britain the question "fighter or fighter-bomber?" had been decided once and for all: The fighter can only be used as a bomb carrier with lasting effect when sufficient air superiority has been won.
Of course, the outcome of the war would not have been changed. The war was lost perhaps, when it was started. At least it was lost in the winter of '42, in Russia.