And is it a good thing?
By implication then, not only is common sense acquired, but also no one below the age of 18 has fully acquired common sense... interesting opinion IMOI think Albert Einstein said it best: "Common Sense is the collection of prejudices acquired by the age of 18"
Not saying all common sense is wrong, that's just true at all. Just saying some are pretty far from being 'right'. But that's a story for another day.