From my experience in walking with my spirit, I encountered nine (9) levels or substages of development (maturity) and then three (3) more while in the love that is God in my Complete (True or Genuine) Self.  These are also shown on the map on my website.  If you are allowed from the time you are born to have the holy spirit in you and the churches and parents honor that spirit in you rather than always thinking of you as a child or their child instead of you as your own complete self, the timeline below will be pretty close.  The timeline stops whenever their is trauma by not allowing this, especially at a very young age.  This takes parents and leaders who are true adults themselves.  The starting age of each level or substage is when a person becomes serious about that particular level.