I hear that the ratio, roughly, is 3 hens to one box. So I think you're good.
If it were me, I'd get day old chicks to be able to socialize them more with humans and watch them grow. Of course, they won't be laying eggs for another 18-24 weeks, but you'll have too much fun with the little bggers to worry about waiting.
However, if you'd like eggs soon after you purchace the hens, shoot for pullets. Just be aware, when chickens are grown, they may take longer to get used to people, not like the chicks who'll follow you around like 'Mommy'.
When it comes to taming chickens, you can do a few things. I find it best to hold some corn out in your hands, where they can see it clearly, and try to call them over softly. Let them take some corn, and see you're not a threat. After a few days, they'll begin to warm up to you. Then you can begin to hold them properly. Don't, however, be surprised if they're a little freaked out. They still don't really know you.
With chicks, it's a bit easier. Merely staying with them can form a bond quickly, as they don't see humans as threats. That's the best thing with chicks, they latch on quickly. You should let your kid get close to them with some food in the hand and feed the babies. Just be careful that the little guys don't know when they peck someone it hurts. They'll get better at it.
Good luck!