My 3 month old puppy has a bad temper

Hi!

I recently got Leon who is 3 months old from a puppy store. He is adorable but i am having some second thoughts because he is being very aggressive towards other dogs and has growl and snap at my 3 year old daughter. I hired a professional trainer and is going to start the classes this week but i wanted to ask you as a JR expert... is this problem manageable? after he learns obedience and discipline going to disappear? I am already socializing him with other dogs and taking him out so he gets used to different types of people...

Thank you very much for your time and this helpful website!


AO