I bought a trio a few weeks back. From day one I got a white egg per day. After one week, I got two eggs, one white, one blue (yay me!), then back to one white egg a day for a couple of weeks. For the past couple of days I'm back to two eggs per day *yippee*, one white and one blue.
I'm not precisely sure how old mine are to be honest, but I do know they were last year's hatch but not one year old yet.
I think your's should come into lay anytime now because they are mating. My drake has treaded both of my girls since they arrived, although his major preference initially was for one particular female (whom I'm now assuming was laying the white egg) but is now actively getting excited about both of his ladies with a fervour he wasn't showing before.