I had a dog that walked 5 miles a day. She would not fetch. Tried from puppyhood on, no interest. She was high energy.
I have another dog now that will fetch and bring me the ball (from the day I brought him home at 7 months), for hours, I have to stop him because he doesn’t know when to stop, he will collapse from exhaustion. This same dog will not walk more than a mile or two without lying down.
I find it takes a dog at least a month in a new home to start to adjust and understand rules.
In the meantime I would start gentle training.
Give her some time, right now she’s being a goofy puppy. She was probably pent up in a cage/crate at the shelter. Take her for long walks to get rid of some of that energy, at least an hour a day. You may find that she is calmer and more receptive to training.
Are you near a clean lake? With the breed mix you mentioned I bet she would fetch if you threw something in the water?
