How did you know when you stopped being a boy and became a man (if that's how you identify)? And if you're raising a son, how will he know when he's a man?
Rites of passage are critical to our development as humans ... but they're sorely missing from mainstream culture. Indigenous cultures and first nations have much to teach here.
A big issue in mainstream culture is that there's little guidance for dads on how to guide boys into becoming the healthy masculine. There's a lot of talk about toxic masculinity; we know what we don't want, but how do we teach boys what we do want?