I know its a silly question, but I can't think how else to find out. My unexpected, Light Brahman rooster, Marion (was Rosemary), is now 6 months old and has been crowing for about a month. He still has that teen boy, voice-breaking, rusty door sound -- especially for his first few crows of the day. How long does it take for a rooster's voice to settle? So far at least he's a well-mannered crower who greets the dawn and doesn't have much to say for the rest of the day. I saw him chasing the most mature of my hens for the first time this morning so I know his adolescence is well under way. I did a lot of research on chickens, but I wasn't expected the awkwardness of the teenage crow. Its so funny! Especially since I have a 13yo son whose voice sounds just the same.
It just depends. I've got a 10-wk-old Fayoumis/EE cross who started sqeeking boy-noises at 6 weeks, and now has a decent sounding crow. I'd bet that in another month yours will have a more developed crow.