grumpy old girl

Question
I have a dog who wants nothing to do with other dogs.She is a mongrel in good health and is 11 years old. My daughter has a cavalier who is about a year old and my son has a jack russell puppy if either dog go near her she growls at them.there is no problem if they leave her alone how can i help them become friends.I also have a jack russell who is friends with everyone and they get on really well although it took a while at the beginning.  

Answer
Unless your dog was well socialized to unfamiliar dogs of all ages and sizes when she was young herself, it is unlikely that she will ever be that thrilled with being bosom buddies with your childrens' pets, although with time she may learn to tolerate them the way she does with your other dog.  The good news is that she warns them, and they seem to be observant of the warnings.  One way to encourage her to accept the other dogs is to feed her some treats when they appear, and discontinue feeding when they go away.  She will at least learn to associate them with good things happening for her! Be careful not to have the other dogs mugging you for food at the same time.  They need only be visible to her, not right near her - you don't want to have it backfire and cause a tiff.  The other dog can be fed by its owner at the same time so that each dog is aware of the other's presence, but remains focused on their own human.
It's very common for older dogs to become less tolerant of, and to start warning or disciplining, puppies as they reach adolescence, so her behavior may not be "abnormal".  Also, it's a survival mechanism to be wary of dogs that aren't in your own pack, so that isn't abnormal either, but savvy owners counteract it by socializing their pups well when they are still between the ages of 8-16 weeks!  
I hope this helps you understand your dog's behavior better, and prepares you for the next time you have a young pup yourself.