New Hampshire red

[AATH]

Ok so my 8 week old New Hampshire red already has his/her comb turning red. However the tail feathers are still real short. When sexing is it more important to look at comb or tail feathers? Here's a picture if anyone can tell.

 

[AATH]

My red sex linked still has no color in her comb at 15 weeks. That's why I'm concerned.