How old are my Bantams?

There is no really reliable way to tell their age.  If you can post pictures here, some of the experienced members might be able to have an educated guess at how far they are from laying.  A clear picture showing their facial features (comb and wattles) would be a big help.

At this time of year (autumn) your girls may take longer to come in to lay than they would if they reached the same age in spring.  Depending on your local climate and daylight hours they may decide to delay laying until after the shortest day in December!

If there is one thing chicken-keeping teaches you, it's that you can't rush Mother Nature. 

This is the one which looks older to me.

Thank you Lindeggs and Bantam Novice, sorry for short text on photos, had a problem trying to attach them.  Hopefully the photos of them both are clear enough. 

Hi I'm certainly no expert but I also have some Pekins which I bought recently and I have one who is 20 weeks old and began laying 2 weeks ago. Her comb is very much redder and bigger than yours and she is also very much bigger.
 My other one is a black Pekin and was told she was 12 weeks old when we bought her and she was more like 5 weeks old!! Therefore she is now 10 weeks old, as we got them 5 weeks ago, and her comb is still quite small and she is half the size of the other one. Hope this is some help to you.

Whether frizzled or not, they are gorgeous girls and I agree - much younger than you were led to believe.