You might want to consider any of the truly adjustable bows Hoyt makes three Kobalt & Trykon both go down to 20#'s, the Trykon Jr as low as 10#. The average for an 11 year old just starting would probably only be between 10-20 #'s.

We helped a friend out, he bought a Hoyt Banshee.
The Mathews Ignition starts at 20#'s

Good luck! If you find a bow suitable for a 2 year old, let me know, he keeps trying to steal mine to go "deer hunting"