She looks very normal and ready to lay. But when the days shorten, as they have for the past month, many hens and even pullets will stop laying. It's possible this girl will wait until Spring to start. That is not unusual.
I would give her some more time as well. She may have a problem with her reproductive system or she may just be a late starter. Pictures might help. If her comb and wattles are huge, it could mean she has a damaged ovary and will never lay.