Don't know...most guinea pigs I've ever owned tended to die if I looked at them wrong. They also made a really annoying "REE-REE-REE" noise. I don't see why people like them as pets...it's like owning a retarded quadruple amputee cat.
I have had 4 guinea pigs, my first one lived until 5 (nearly 6) my second one was a rescued guinea pig so not too sure how old she was when we got her, but I would guess she was about 6 when she died. My last two were 7 and 8 when they dies and I miss them soooo much!! Some websites say the average age is 5-6, some say the average is 7-8. Other websites say 8 is old for a guinea pig, and in my experience it is. I would say around a good age of 6 or 7 is about average.