She's just a baby!
My best advice would be to NOT use the word come unless you can make her come to you. Everytime you use the word come and she goes the other way or holds her ground, you are reinforcing the fact that she only needs to come when she wants to.
YES! Training will sort all of that out. In the States, the class that we usually put our 12 week old pups in teaches some very basic behaviours and is GREAT for puppy socialization. I highly recommend it.
After puppy class, you get into the "real" obedience. And in my opinion, the real fun! As you and your pup learn together, you bond and the rewards are endless.
Keep at it. Enjoy this wild puppy time because, much like children, they grow up way too fast.