I don't find that there is any perfect age at which a child should start taking riding lessons. The individual child's personality is key. I myself didn't start taking formal lessons until I was in highschool, despite being around draft horses my whole life and feel that I am a competent horsewoman.
I have seen children begin riding at age four though, and do quite well. My advice would be to begin lessons as soon as you feel the child is able to follow instructions and is open to learning. The younger the child is when they are first introduced, the better the rider that they will end up being, however if you decide to put a very young child (such as a four or five year old) into lessons, you need to make sure that their instructor is experienced with children and that the horse they will be riding is very calm.It would be very unfortunate to have a child be scared off riding from a fall when they are young.
Research show around the age of seven is a good time to start, However the size and maturity of the child comes in to play as well.
I cant really gove you an answer,but what I can give you is a way to a solution, that is you have to find the anglde that you relate to or peaks your interest. A good paper is one that people get drawn into because it reaches them ln some way.As for me WW11 to me, I think of the holocaust and the effect it had on the survivors, their families and those who stood by and did nothing until it was too late.