I think the perfect size baseball bat measures 26 inches in length and 18 oz in weight. In addition, to get the right baseball bat size must also be based on the weight of the child. To see if a bat is right for her, you can test her out and have her try on several different bat sizes.
Have your youngster position the bat's knob starting at the center of the chest and continuing sideways through the arm and into the index finger to see if the bat is too long for them. She has the perfect baseball bat length if she can grasp the barrel's end with his hands.