Aggressive Female maltese puppy

Question
My 13 week old maltese is very aggresive. She "mouths" a LOT, and while we play fetch she becomes very aggressive growling, biting. I have no children and spend most of my time with her, and she has every toy known to man. I adore my baby more than anything. Ive enrolled us in a obedience class that starts next month. Any advice on what i should or should not do in the meantime? Thanks in advance!

Answer
The class sounds like a great idea, i hear this a lot with maltese you need to stop this escalating to agressiveness choose a form of punishment and adhere to it i suggest when she does unwanted behaviour firmly say no pick her up and place in her basket and make her stay until you let her out leave her about 3 mins depending on seriousnes then like with a child say ok the come here and then she will "hopefully" assosiate negative behaviour with the basket and help prevent it but dont be soft even if you feel your being harsh because think of it like this how bad will you feel if it escalates to her biting some one.
Good luck
will you let me know how the class goes as i am interested in their effectivness and teqhniques
bye
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