PSYCHOLOGY
According to Brian Allen can't keep their innocence as they grow up because for one their curiosity will make them curious whether it be early on or later on down the road, children might be able to keep their innocence for a good amount of time but if they get exposed to anything even just one concept they will have the curiosity to want to explore it all or in their mind to discover new things. Most likely children will find out sooner or later whether it be glom friends, family, or they hear it from their parents, etc, they will find out sooner or later. From a psychological perspective a child cant keep their innocence as they grow up.