6 months is when, on average, most hens start laying. Keep in mind that is just an average. Some hens start earlier, and some later. If you read through these forums you will read of hens not starting until they are 7 or 8 months old. For pullets who come of laying age during the shortest days of the year, it may take longer.
I have two SS pullets right now that are 20 weeks old, and they look similar to yours in terms of how red their faces and combs are. I'm thinking mine are still a few weeks away.