I have 8 grandchildren, from 3-7 years old. One, who is 7 now, has always wanted to shoot with me. He was drawn to my buckets of arrows about as soon as he was able to walk, to the chagrin of his mother who was afraid he would poke his eye out, and drawn to my bows soon thereafter. I bought a 15# bow, for him and the other grandchildren to use, and he started "shooting" it when he was about 4. He was actually shooting arrows with the intent of hitting something by the time he was 5. Whenever they come to visit, shooting arrows with grandpa is a must on the agenda, although his parents haven't encouraged him in that direction at home, preferring more group oriented sports like soccer.
I have a granddaughter, also 7, who shoots as good, or maybe a little better, than my grandson. When she shot her first arrows a year or so ago, with perfect form with minimal instruction from me, I thought, "wow, I really have a winner here!" But her interest level is not as high as my grandson's, as she prefers indoor activities like crafts and asking millions of questions.
There may be some interest in the younger ones, but nothing evident yet. With anyone that age, their interest fluctuates and changes daily, if not by the minute, as they begin to explore life. I think my job is to just make the bows and arrows available to them when their interest turns in that direction.