Grow Out Of Meaning

(idiomatic, by extension) To become too mature for something.

Example: To emerge from (something); to take a particular shape as a result of (something); to come to exist from (an origin).
  I give my old clothes to charity when I've grown out of them.
2002, House of the Seven Gables - Page 37
  Still, I see you mean well enough, and are merely suffering from the debilitating cheerfulness of youth. You will soon grow out of that.