Hi, my two staffies never matured they were like a pair of little monkeys! They could behave like good kids then naughty mischievious ones next! Thats what I loved about them. I had mine 13 and 15 years respectively...and miss em lots! I suppose its whose definition of mature and good training. Mine were well behavied in public but bounced with energy when ever they thought they could get away with it. Train him/her well and love it lots.