It could just be puppy excitement and the classes will help her to realise that she doesn't have to bark at anyone or anything.
My o/h was down the park yesterday with Diesel and he bumped into a couple with a 4month GSD bitch....she was really gobby, kept barking at every dog down there. She ran at Diesel barking a few times but he just ignored her but she kept barking at him until he'd had enough and told her off - she stopped immediately and sat next to him quiet as a mouse
