Lots of great answers from pp, but I thought I'd weigh in too
if the base of a comb isn't straight, then that's a problem. It's not one of the first things worked on when improving our breed, ie weight/shape/quality of flesh and bone, but in the end it will matter some. If the base is straight and the comb itself is floppy in your girls, this is not a problem. If the comb is wickle shaped then you most likely have a bird with a cranial hernia. These should be moved away from as much as possible if your desire is a straight comb with crest. A few of us have also had cockerels with floppy combs straighten around 1 year. I've found that 1-2 years old seems to be a great time to evaluate combs, including individual bird's ability to cope with the cold. HTH and best wishes