[2ndhandgal]

7 months old is definitely not too young for teenage. They start to push the boundaries and now is the time to step up training and management - if they get away with it they will continue to behave like this so you might need to go back to using a long line if recall goes out of the window and carry toys to swap stolen toys with to give back to their original owners

 

[2ndhandgal]

She has learned that she gets a better game with stolen stuff than her normal toys so you need to reverse that - I would put her on lead anywhere near other dogs playing with toys for now while you work on it as that is going to become ingrained behaviour otherwise. You can then work on "her toys = good game and great fun" - "stolen toy = ignored and no fun at all" - set her up with a friend and a toy she can steal