Most people seem to want a heavier bow for the kids, than the kids are comfortable with. The average 10 year old girl that hasn't shot much, will shoot best with about 15#@22", with a 48" bow. Taller girls, over about 5'2", will need a longer bow. Our M-54, 25#@26", is very popular with youth up to about 5'8" tall.
We take our bows back in trade when the kids grow out of them, at 75% of the original price. This has worked well for years, with many kids shooting our bows from the M-35 up to the M-58 over several years. Hurts less when the time comes to go to a longer bow.
Chuck