My kids are 10 and 7.  I have a 60" 35#@28" Bear Black Bear that my son shoots, but it's a little heavy for him.  I'm currently refinishing a 62" 25#@28" Bear Ranger that'll be a little easier on him and should be light enough for my daughter as well.  They work fine at short draws but will still fit even after they outgrow the weights.  That's why I recommended the Prairie Predator.