It shouldn't matter if the bird is 7 weeks or 7 months. The one pictured has its adult feathers. With a better pic, it's sex could be determined. Don't forget that both sexes have saddle feathers, the girl's are usually rounder and fatter. The boy's saddle feathers are usually more curved, longer, and pointy.At 7 weeks, there are no saddles to sex by.
And don't forget the hackle feathers in its cape. They tell sex too.
But who knows? I could have my sex feathering all mixed up!