59
Superman has probably seen his parents have sex
(programming.dev)
A "Showerthought" is a simple term used to describe the thoughts that pop into your head while you're doing everyday things like taking a shower, driving, or just daydreaming. A showerthought should offer a unique perspective on an ordinary part of life.
I believe the point is, usually your kids don't have the power to see through walls. Of course I'm pretty sure most interpretations of superman, Depending on the interpretation of superman, he discovers his powers between 12 and 18.
He probably didn't have a choice no matter when he got the power - I doubt he knew how to control it right off the bat.