You have a few weeks left to go, although the Red Star are fantastic layers, and will lay about the earliest of hen, they will start about 20 weeks old. Now you might get one or two who will start a week or so ahead of that, but don't get your hopes up till around week 20, then you should be getting that magical 1st egg!
Signs that indicate getting close, bright yellow legs, bright, bright red combs, the egg squat when you come up to them are all signs that within the next few weeks you should be getting some eggs.
You think it is long to wait for them to lay.....wait until you set a clutch of eggs under a broody hen, I swear the 21 days is an eternity! I am on 15 days, one more week....oh! I better be getting some stuff ready.