Victorinox has a great 'first knife' for a child (or adult). It's a red plastic handle single blade which is sharp but the end is perfectly round, no tip at all. When children hold a knife it's most often the tip that causes a problem poking into something it shouldn't (like his sister). Fewer injuries are from the blade edge.
I have 4 children and what i have learned (somewhat too late) is to not 'push' a child into something because i am interested in it. But when they have an interest in something, then the teaching/learning goes much better.
A child can be interested in using a knife at age 6 or maybe not until 15, so the knife parent needs to be patient.
None of my children (oldest is 38) are particularly interested in knives, but they do joke how for every birthday they always got a knife from dad. And dad replies, "ya, but it was always a decent knife !".
kj