Losing my mind over puppy

For context, we got our puppy back in February due to an emergency situation. The previous owners dog's had puppies, and the mom was very aggressive to the puppies, so they needed to be rehomed quickly. We had her since she was 5 weeks old (yes, I know very young), she's now 14 weeks old. She is VERY high energy. She is crate trained, and about 90% house broken. She knows her name but has terrible recall. I've been training her at home and she is very smart. But I feel like she doesn't want to listen. After weeks of training with her, all she knows is sit and occasionally down. We have two cats that don't really mind her at all, but she is constantly going after them. My cats definitely give her a warning smack if she gets too aggressive, but I feel like it doesn't phase her at all. She is always running trying to bite at our feetThe previous owners told us she was a Newfoundland/golden mix, but yesterday we received the results from her DNA panel and the majority of her DNA is 34% German Shepard, 23% Bouvier des Flandres, 17% Golden Retriever. Which I feel explains her personality so much more than a newfie/golden. What I'm trying to get at is, does it get any better? Any tips? We have been under the impression that she was mostly Newfoundland, but now knowing she is mostly German Shepard, I feel like we may be in over our heads. I'll be putting her in some training classes once her last round of shots are finished(in a couple of weeks).