I'm a first time chicken person and have a 9week old buff cockerel. At 4 1/2 weeks he started crowing at 6 he tried to mount one of his more passive flock mates. The bossy girl of bunch rushed in and knocked him off. She flew in feet first and hackles raised. The cockerel ran to his hiding place. I haven't caught him being frisky since. Also, after getting knocked into place he started taking care of his girls. Making sure everyone leaves the coop and everyone goes to bed. He herds the girls out of my way when I'm carrying waterers in the coop.
Yours might just be an earlier bloomer that's trying to get a handle on his hormones... eventually he will learn manners or will need other accommodations.