I am an adult because I get treated like one. If you treat a toddler like an adult then so he is. "We are children inside" just means the adult stuff is layered

I am an adult because I get treated like one. If you treat a toddler like an adult then so he is. "We are children inside" just means the adult stuff is layered ontop of the child stuff, it does not mean in our essence we are children but rather the sum of our whole life as we remember it from childhood to old age is who we are as opposed to a snapshot of how we appear today or in the past.