I've seen the one pictured, she's around 1000 g's and probably one of the best looking snakes i've ever seen
She just seems to get better with every shed.
First one was produced in 2006 if I'm not mistaken. I'd probably be pushing it by saying 2005.
You're right, I'm still thinking of 06 hatchlings as last year.
As far as what determines a snake as being adult -- I'm not sure about everyone else, but I don't consider adult size the same as being adult age. I usually assume that when someone asks for adult pictures of a morph, it's because they want to see how the colors age. A 1000 gram pastel who is one year old is not going to have the same coloring a few more years down the road.