old cat, new neighbor

Question
My family has a cat (female) that'll be 20 years old this December. We've never had any other pets while owning this cat. My aunt is thinking about moving in with my parents...and she also has a cat (female). Her cat, is about 8 years old. My question is this: do you think it could be detrimental to the health of our cat by having my aunt's cat move into my parents house...having never shared territory with another animal? I also might mention that our cat is only friendly to her immediate family. She doesn't allow many strangers to pet her, and hates little kids. I've never seen her reaction to other cats.

Answer
Hi Brett!  I would try introducing the two cats to see how they react to one another.  Hissing and growling is normal when cats first meet, but if either become very stressed, I would definately recommend keeping them separated.  They could still co-exist in the same household...just in different areas of the house!  Your cat is an elderly little lady!  A 20 year old cat is something to be proud of.  I wouldn't want to have her become very stressed and risk her health, since you have mentioned that she isn't fond of strangers and has always been an only pet.  Her and your aunt's cat may never get along, but like I said, see how they react to one another, and if it doesn't work out, just be sure to keep them separated.
Hope this helps!
Hilary