I know that development is a lifelong process and that as humans we're constantly changing and evolving, but at what point in one's life would you say his or her type "solidifies," or reaches maturation (kind of like a type puberty)?
To elaborate, say a person is ISTj, for example. We all know the teenage years can be somewhat tumultuous and that teens are less responsible, decisive, and authoritative than adults. In lieu of this, would momentary lapses in responsibility and judgment be typical of someone that age, even an ISTj? I use this example because I have a few male ISTj friends who tend to procrastinate, drive recklessly, and disregard schoolwork to the point of flunking out.
Also, many types, specifically some of my ENFj friends, were once very quiet as youths and adolescents, but became very outgoing during their late teen years.
So, in a nutshell, when would you say a person's psychological type manifests itself most definitively?