There has been little, or nothing, written on becoming and adult. People don't teach it because, in reality, there are few adults out there. The only course that I have ever seen on it is the Navigator Series.
There are many different aspects of growing into adulthood. One of the basic steps is to forgive and let go of all past hurts. This can be done with something as simple as a decision, but there are specific contemplations which are designed to accomplish that. They are too lengthy to post here and require a little hand holding.
Look around you are what purports to be adults and you will inevitably see children in an adult body. Watch how they behave and you will almost always be learning what NOT to do and how not to be. Life as an adult is far more fun and rewarding than as a child, counter-intuitive as it may sound.
Love ya, Jed.
Love ya, Jed.