if you go with the 10/22 there are probably 100 different stocks available for it, maybe 20 different barrels, 5 or 6 trigger assemblies, etc. etc.
You can spend $200 on a basic 10/22 or you can buy a "aftermarket" everything and spend $1500 on a "10/22". buy the basic 10/22 and then spend some money on upgrades or changes to fit the kid.
My 7 year old daughter is showing some interest, been looking for a deal on a Crickett or Rascal but will take her somewhere and see how the LOP is on those, or if I should just get her a different stock for one of my 10/22's.
So many people change out the stocks, a new take off stock can be found easily and cheaply. Measure it to your kid and cut it exactly where it needs it. You can cut and glue a mouse pad on it for comfort. And it's easy to keep adding back 1/2" of stock as they grow up.

