Both of my kids grew up with all types of animals from day one and were always interacting with them to some degree,and they were always supervised closely. My son is now 11 and is just starting to be aloud to handle some spiecies unsupervised Ie some ratsnakes and bp's.
I think the bigger problem is the more comfortable young kids are with snakes the better the chance they my be picking up wild snakes they find in the yard, although not a huge problem in south central ont. Canada but in places with venumous snakes Its never to early to teach spiecies Identification for your native herps.
We can control what goes on in our snake rooms, but we cant always be standing over them playing the back yard.
Just my thoughts Jason