Breeding age in emeralds varys just like people some grow larger faster and others take time. Also if you "power feed" them they tend to grow at a much faster rate, I honestly don't think this is right? Usually females if fed right at good size(4.5-5 ft.) takes around 5 years, males are ready when they first display interest, usually 3 ft + arround 3 years. Note that it is usually a good idea to keep males small, the smaller males tend to intimadate the females less.
Size of litter ranges usually from 0-12 and not often higher. Many people think that litter size is directly coralated with the size and weight of the female but I have never seen any studies, though it does make sense.
This female dropped 7 live 1 still born and 2 slugs last year on her first attempt, from what I have noticed still borns are common for first time breeders.
<img src="http://emeraldboas.com/projects/Birth11-16.JPG"/>
hope I have helped
Joe
www.emeraldboas.com