Mine have gotten a little bigger, but at almost 9 months old, they are still not as big as a grocery store egg. (except for the double yolkers) It's my understanding that after they go through their first molt (usually around 1 year old) the eggs get bigger.
I agree. They will gradually get bigger but the best size jump is after their first adult molt. They may get a little bigger after later molts, but it will not be as dramatic.