Should I rehome my puppy? Please help!?

Background info: 

• 14 week Old English Sheepdog Female 

• We currently have a 5 year old Sheepdog male. 

• Have owned puppy for 6 weeks. 

The vet came by 2 days ago and told us the puppy is dangerous. She said she has fear issues and that it is most likely genetic. The vet said that she could kill our other dog and or us or someone else. The vet said we have a 10% chance of not getting bit bad when she is grown. She said she needs to be rehomed and given to a facility where they can deal with fearful puppies. We are heartbroken and don’t know what to do. She is 100% perfect with us, but when she saw the vet and our grandma she growled and barked. The vet said she should have been able to smell that my grandma is related to us and been okay. The vet said her brain doesn’t process fear correctly. We don’t want to give her up. We are seeing a veterinarian behaviorist in 2 weeks. Please help, what do you guys think???