Individuals will vary, sometimes widely.
If you look close, most young males will probably show little buttons or nubs where the spurs are beginning to grow by 3 months. All the cockerels I have had grew thick nubs that were around 1/2-3/4" long by the time they were 10mos, with sharp tips growing off of those. They won't likely be full blown spurs with sharp point until around a year. Again this varies quite a bit.
I think crowing has plenty to do with the presence of other males showing them the way. I have heard stories of crowing in the brooder, but mine have started around 3-4 months. An adult cock leading the way every morning will inspire them earlier, while raising the first batch of biddies with no adults around would lead to him crowing later as the flock needs him to lead the way, no matter his inexperience.
As for the wing dance and other courtship rituals, my old flock leader was courting the 1 month old biddies right off the bat, as I got him around 7 months to protect the little ones. I guess he had never been around females yet. IT quickly wore off until they came of age. The young rooster in training started showing off for the girls by 4 months, but it was mostly chasing them around and then in turn being chased off by the big roo. Again, it varies, but with courtship rituals I think it has a lot to do with being around females. Boys raised in a rooster pen may show later than those being in with girls.
Nothing scientific, just my own observations.
Ken