This is one of the hottest subjects in the Avian World.
With young Parrots, one want them to be able to fly as part of the Healthy Development of their flight muscles, which drive their Heart and Air Sacks (Lungs). Once they have flight handled, one can consider a light clip of the Primary Feathers as you have done.
As so well stated above, the goal should always be to cut, no more than just enough to ensure a 'safe' flight to the floor.
Children and Door Safety: We seem to be able to train children to close the door during the Winter, so we should be just as good at teaching them 'Bird' safety regarding doors.
Our Grandkids, picked it up quickly and have turned into the Door Police as they watch anyone that even gets close to an exterior door.