I'm sorry to say - if this is unwelcome news - that although you all keep calling this chick a "she", it is almost certainly a little boy - it is the way that McMurray's helps to get rid of excess male chicks. Just probably ought to count on that.
Well, according to everything I have read about this bird, is that they are extremely quick to mature and the roo's may even begin crowing by six week of age. Mine are not crowing yet, and they are three months old.
What else did you order? There is no reason to believe you have a rooster until it shows its sex. We got twenty five hens, got a total of thirty birds and so far I have identified only two roosters. I know there will be more roo's, but we keep praying : -) ; -) : -)