Sorry but I disagree that she is too young to be taught the word "NO" (The Sooner the Better). She has to learn what is appropriate behavior and what is not. Yes .. Play time is a must in a young pups life but
leadership and discipline are also just as important, If not more!
Take this example for instance: my husband always let our pups at a young age chew on his goat tee. It was out of control, they would lunge at him every time he was holding them. It was so out of control that they started to do it to the rest of the family and even tried to do it to my friends daughter who was only 18mo old at the time. I would always catch him allowing them to do it .... And I would correct the pup and the husband. Finally one day he was sitting in the chair and up came the pup and bit him right on the chin! Pretty hard, that it drew blood.
My point is that it is learned behavior.....If you do not nip it in the bud, put a stop to it right away the behavior becomes part of who they are and will be harder to correct and rectify later in life.
I say pick your battles.... Let the little stuff go, but never sit back and allow a pup do something that could become a problem in the long run.
I always use the Shaker Can method with my pups. You can find the direction for use on my web site.
http://dawnsyorkies.piczo.com/?g=33521666&cr=7#