The Bite Stops Here
It's very important that you teach bite inhibition now that your dog is in her formative years. Therefore, I would refrain from being physical with the dog when this occurs, and if necessary, employ a crate when your pup is overly stimulated. The above method works well if you're consistent, and do not attempt to confuse the dog with physical manipulations. Some dogs are more persistent than others, and these dogs require you equal or exceed their persistence with this method. It's very important that you remember this is about how to teach your dog to bite softly, not to stop biting altogether. Dogs bite, this is a fact of life, and when they do we hope they do so softly.
Have you considered a puppy class?