My EEs came into lay between 20 - 26 weeks old. Not too bad.And that's what I'm looking for, beautiful blue eggs like yours! The EEs were a happenstance from another BYC member; had about 15 from one to three months old at a very nice price if I took the boys too. Some are EExEE, a couple EExblack australorp and some EEx lavender orpington. Several roos in there. I'll only keep a roo from a EExEE breeding and will cull out the girls as necessary. I'm afraid I was under the impression that EEs came into lay earlier, layed better and sometimes with bluer eggs than pure Ams. So I'll see how it goes. As each age group comes into lay I will try and tag the earliest layer of blue eggs and will consider those to be the ones to breed from. I have also thought about looking around to find some pure Ams that lay nice blue eggs but are show quality for my 4H kids, but think I'll hold off expanding for at least a year.
My EEs lay bluer eggs than my pure Ameraucana bantams, though not as good at the consistency. I have quite a few EE x BR and hope they will lay better because their father is from really good lines of layers.

Your EE x Black Australorp should be better than EE x EE for laying.
Though any blue laying EE crossed with a brown layer will only lay brown or green eggs. You'd loose the blue by doing that. If you want to cross them out to a higher producing breed, yet keep the blue - do it with leghorn. That should really improve the laying!