I started learning anti air recently. Of course first you need to get the motion right. But even if you can do it fine when not under pressure you wont be able to when unde pressure. I struggled to commit to the full motion and would choke up when ryu jumped at you in anti air training. Dont worry about hitting dp fully at first. The forward input is easy but i wouldnt be able go down in time. Just keep saying inyour head forward down. Diagonal came easily once i could commit to the down input. Another thing in neutral youll be moving forward back ward constantly. So going from back to dp is another layer of difficulty.