Hen not laying!!!

I have a 22 week old Easter Egger hen, but she hasn't laid yet. The only reason I am worried is because her two sisters started laying at 19 weeks. They are all from the same hatchery and are the same age. She hasn't even showed any signs of laying yet. Her comb is getting somewhat red, but she hasn't "squatted" yet so I know she's not even close. Also, she barely even has a comb which I think is odd because her sisters have noticeable combs.
When do Easter Eggers normally start to lay? I heard they usually start laying at 20 weeks and some haven't started until 27 weeks old! I hope mine will lay soon, what do you guys think?
She didn't really sit still for any pics, I will try to get better ones tomorrow.