Egg laying question?

So one of my chickens just started laying this week and she is 18 weeks old and think one of the others isn't far behind now, as well as a about four of my others. But, my question is, will their eggs get larger as they get older? Right now they're pretty small. The hen that started laying is a red sex link, as well as the one that isn't far behind. The others that I think are getting close are rhode island reds and black copper marans. All the ones I think are getting close are showing the usual signs, their combs are getting bigger and starting to be more floppy as well as starting to get a little redder, also they are all starting to fill out their backsides. Are these true signs? Or am I just wishful thinking? Ahhhh who knows. Lol!

 

Thanks for the info...this is my first flock and I never really been around chickens before but I must say it has been quite entertaining thus far! Chickens are a trip to just sit and watch! They do some of the darnedest things...lol!

We mainly got these guys for eggs...did I pick good breeds?

2 red sex links, 2 rir's, 4 black copper marans, 3 Americaunas or Easter eggers...they have green tinted legs and feet, 2 Delaware whites...I think, and 1 black australorpe roo...I think....would like some opinions...thanks!