I bought bamaboy a Cricket when he was about 7. He shot it under intense supervision with .22 CB caps to limit noise and the distraction of muffs. I could coach in a normal voice, the rifle sounded like a pellet gun.
We moved up to .22lr and muffs pretty quick. I think starting a kid with a reduced size .22 single shot and iron or aperature sights is the way to go.
At some point the Crickett developed an extraction problem. I called the folks in PA and they had a UPS truck at my door THAT DAY! In about 10 days it retuned, complete with a nifty case..... free! It ran fine ever since, though we don't shoot it much anymore.
That was 10 years ago, if the outfit and quality is the same, you won't be disappointed.