What is Old Age?

I came across About.com Senior Living and read people's responses to "When do you think old age begins and why?" There were lots of the standard it's not the number but how you feel type of answers. The common thread I got from these people was that they were active and enjoying their lives and had connections to their community. The other comments were physical decline and loss of independence as signs of old age. One person summarized it nicely and said "you are old when you give up". It's not so much what you've lost in looks, physical abilities or independence but what you plan to do with what you have left.