It will depend on your set up, your kids and breed of geese you select.
Everyone will say their kids are great with animals. Many really aren't though.
June - December we have very little concern with our geese and our son who turns 3 in January.
He if course has grown up around them. Has been apart of chores from feeding to evening lock up. He has been allowed to help herd/guide all summer this year.
We dont leave him alone with them, but the geese also give him the same respect they give us.
Breeding season we require he holds a hand so he us near us for round up.
Our society tends to lean towards "bubble" raising kids. We dont happen to agree with the concept of never being dirty, protect from every single possible scrap, or that everyone gets an award/ribbon. We prefer he experiences things first hand, gets dirty and understands rewards for hard work.
At not quite 3 he knows how to count to 20, his colors, abc, shapes, animals. He also knows were a lot of his food comes from since we raise chicken, duck, goose, turkey, and rabbit.
I say be honest with yourself about your kids and how they handle themselves. Be honest about your set uo and ability to provide housing for the geese and fencing when needed to keep the two separate. Then be consistent from day one about rules.
Our big ones are no chasing the animals, no swinging sticks, no throwing things at them. Close all gates behind you, move slowly and talj to them as you approach.
Good luck on yoyr goose search.