Comb Questions

I know it can vary from chicken to chicken, but I was wondering if sometimes pullets can have a growth spurt of a comb, and then thats it. Nomore since. I will try and get pictures up later on tonight, but I figured I'd ask anyways. She's the largest chicken out of the 5 I have. They're all different breeds though, and she's a barred Rock. Which I've heard can mature faster? Her coloring looks like a pullet (black with white stripes), she doesn't have any saddle feathers or anything coming in.. she does have a large comb. She developed it at around 4-5 weeks, and it really hasn't grown anymore since! She's almost 7 weeks old now. It's fairly pinkish/red, but I still don't know. I haven't heard any trying to crow or anything, and she just acts like a pullet. My question being, since Im new to chickens, am I totally off in thinking could she just possibly have a larger comb for a pullet?? Or is the comb the end all- be all, she's a roo? I'm still that she IS a she though! I that chicken!