the Pup that I got from Mike for my 3 year old, he'll be 4 in a couple months, is a 20#@21". Sounds like alot, but he only draws about 11" which puts him at around 10#. I figure he will be able to grow with it.
He really enjoys his Pup and can get it to full draw pretty easily. I went with the higher weight because he kept pulling his 15#@20" glass bow back to his ear. I did not want him to hurt himself and he wanted his bow to shoot like his brother's bow. Everybody looks for performance, but I didn't know until recently that it started so young...