You're Doing a Great Thing
I've flown just over a hundred kids in our RV-6. That's not even nearly a record, plenty of other folks have flown hundreds. i had a great time every flight. Kids who are interested enough to take a ride are usually pretty sharp kids, ask good questions and listen to the answers. Every single one did some of the flying. I had about three or four who were reluctant to touch the stick, and I, well, tricked those kids into flying a by making sure they saw I still had the stick before they took it. After demonstrating a couple of turns while they followed me thru, I would always notice the stick moving on its own in subsequent turns. Then I just kind of slowly let go, put my hand on my knee and watch them fly. The look on their face when I tell them they made the last couple of turns is priceless.
I've had to slow down some because my wife is a worrier, but she still lets me fly a kid every now and then. Seriously, you're giving these kids a great experience even if that's as far as they ever go in aviation. At least they had the experience. For some, it's life changing in a very positive way.