Undecided-MAN you live in IOWA, get the kids out from day 1-go for a deer scouting ride or go roost some turkeys. Worst case ya still get out of the house.
We are fortunate here to have the youth season alotted to age 16 and under hunters in this state. If they learn the basics at a young age and are not FORCED to go along, garuntee you they are POSITIVELY effected for their whole life.Note that all kids are not created equally-some will never be hunters-but the least you can do is to expose them NOW B4 the other sides views become more promonent.
Lets take our neighboring state to the east for example--they have all kinds of hunters and no place to hunt. They will not allow you to hunt till age 12--the almighty video game rules the life of a pre-teen by age 12.
My personal hunting with a gun began at age 8 with a parent or grandparent right at my side. I defy anyone to tell me how that time spent in the company of knowledgable hunters is BAD.
Now I too ,along with my father and uncles, teach my son the finer points of the outdoors tradition with a 1 on 1 approach. My son, now age 11 has been legally hunting turkeys since age 7 and deer since age 9.
I think you will find from all the fathers on this site thaT they too spend as much time mentoring they're children in the outdoors as possible. Also, they are more proud of they're childs first squirrel,rabbit or wood duck, than they are of a B&C BUCK.
So, to answer your question. Its never to soon -YOU ALONE have to make the call for each individual child.
See ya outdoors!