I started deer hunting with a .243... having shot 2 dozen calibers on deer... I would now say it's NOT the best choice for kids starting out.
Pros... low recoil, and plenty of energy out to 400y... and that's it.
Cons... crazy loud muzzle blast and small entry.
In my mind, the muzzle blast is WAY worse than the recoil to kids.
For new young hunters, I much prefer the 6.8 SPC or 300 blackout when shots are 100 and in... bigger wound channel, no recoil, and MUCH less muzzle blast than a .243.
JMO... but my kids had no problem filling tags with those 2 calibers when they were little