I have to endorse what john and phoenix have said.
Lots of ‘general’ dog trainers don’t understand the traits of cockers and too easy to label them as hyper.
My present dog is 11 months and she has been the most challenging of all my dogs but as I have had cockers before, I knew she would improve in time.
She can still be a little bitey but when I tell her no, you can now see her considering her options
and then doing the right thing
When she turned into a monster, she went straight in her crate, not as a punishment but as a time out session as she would never voluntarily go in when she was tired. She would then come out a totally different dog.
At 13 weeks your little girl is still only a little baby and if she isn’t being shown how to behave, she will find her own way. Phoenix has given you lots of good advice. The most important and first thing I teach my dogs is a recall. It was taught from the first day home and even when my Maisie was being a little monster at home, I knew that I could rely on her coming back instantly to the whistle.
If you look on the puppy board you will find lots of posts similar to yours which shows you are not alone and may be comforting to you.
The first year of dog ownership IS hard work, but if you put the work in, you will have a dog that will hopefully live over 13 years and will give you so much love, loyalty and devotion.
I read an article the other day that says lots of new puppy owners get “puppy blues” when they suddenly realize that this cute little bundle they got is going to be much harder work than they thought.
You are not alone, just keep telling yourself that she WILL get better because it is true