My youngest son started wiping his own bum at about 3 years old but with help, he is now 5 and a half and i still have to check his bum after hes wiped and nearly everytime send him back to wipe again, he does have severe IBS though so its to be expected. But i just hope soon enough i wont have to keep checking after every poo, sometimes i have to send him back to wipe again at least 4 times and i end up just doing it for him to save him clogging my toilet full of tissue lol x