bud i wouldn't get too upset bout it, shes only a pup and only wants to play, if you start making things a chore your pissing against the wind at that age,in saying that you could built frustration in the pup for the object, teasing her with the ball but dont let her have it, and to do that properly you need to restrict other exciting avenues in the pups life, free roaming, following scents whatever it is ,that floats her boat,,for a few days anyway,,
there is a couple of other things going on too , the pup may not have developed enough drive at that age to become fixated on ball play , bu