Take my perspective with a grain of salt, as I’m someone whom grew up with OT on VHS and Prequels in theaters/DVD releases.
I’m in agreement that OT (4, 5, 6) should be viewed first. It offers an authentic view order; this is how most of the world came to know Star Wars. Then, while you don’t have to watch the Prequels, let your kid see them. Why?
I’ll tell ya, because of the Prequels, it made my love for Star Wars even bigger! Excluding The Phantom Menace (even as a kid, I didn’t bother much with that VHS tape and instead watched RotJ multiple times over TPM), II & III expanded on my imagination as a child. The prequels made it fun as a kid to see new ships, new characters, new locations, battles, etc! I drew sooo many pictures, made many cardboard iterations of the prequel ships, and had a blast reenacting lightsaber duels (especially the iconic one from Revenge of the Sith)!
Fast forward to now, while yes, the Prequels haven’t aged well and while I’ve read countless critics of them and while yes, I vastly prefer the OT, I still cannot fully condemn the prequels due to how it made Star Wars live on and expand into games/novels. Without the Prequels, you don’t get something like Knights of the Old Republic.
So overall, the point I’m driving home is that while you may very well hate 1, 2 , and 3, don’t be the authority to deny your kid to see them.