Young man — Intermediate personal development along the axis Personal life. He is no longer a child, he is almost an adult. Namely, this is an independent person, he can already support himself, he already supports himself, he solves all his problems, he solves for himself. He has the right to decide for himself.
For an illustration, see Servant-Princess-Queen. A princess — young man in the female versionsteroid)
Is the young man an adult?
Apparently, for pedagogical reasons, a young person is often called an adult — to emphasize that he is no longer a child. See Child — Adult
Compared to a human child, a young person really seems like a fully grown-up person. He is independent! If this is important to you, see Education for Self-reliance.
However, to be precise, the young man is not quite an adult yet.
An adult, unlike a young person, has a wider range of care and responsibility along the Personal Life axis: this is the one who created his own family, who brings up children and supports parents.