My maxie is 9 yrs old with same charactoristics as yours and has been that way since we got her 7 yrs ago... we got a new puppy for her to socialize with her he's now 12 wks.. which i might add is a ball of energy..lol he sparked a new life in her ...sometimes i wonder if if he's too much for her but she copes with him... i wouldnt worry too much about her...
