
Hi
I also have Shar Pei - 2 at the moment but have had 3 of them - all uncastrated males!
Shar Pei are generally good with children - are you sure he is lunging aggressively? I know mine are the noisiest dogs in the world and always want to see whoever is walking past and they do try to lunge. I cured this by using head collars (padded haltis). If you are sure he definately growled - I would never let him off the lead. Did the young girl try to stroke him?
I have trained one of my Shar Pei to an advanced level of obediance - we go to school every week and he has done all his life - he's now 3 - but I'm afraid to say they are a stubborn breed and quite often even now he will ignore me! Only ask once and if he doesn't repond just carry on what you were doing. He is trying to train you so you have to ask 3 times and he gets away with it until then. They are also clever little monkies.
As for recall - Shar Pei are very independant and anyone will tell you that Shar Pei and recall are not good together! Do keep trying if you feel confident and have somewhere very safe to let him off but I would say they can't ever be 100% trusted!
Good luck. They really are a lovelty breed and I wouldn't be without my boys but they are hard work!