Why do we want to stay young?

I feel sometimes caught between the world of youth and old, maybe because I am at the age of in between.  I read the ads for cosmetics, anti-aging creams and just do it commercials.  Which one am I?  Do I buy the cream for making my face firm?  Do I buy the cosmetic that will take 3 minutes off my face?  Do I put on my jogging shoes and run to promote my youth? Probably not that!  I feel like I did ( in my mind) at 18.  I still am interested in the world, I still love to read mystery books and chocolate is wonderful.  I look in the mirror and know that I am older.  I have more life under the bridge.  I have lived longer, so I have more wrinkles, laugh lines and tear lines, than I did at 18.  Is it bad to not want to stay 18?  I talk with a woman that has 85 years under the life bridge. She still feels the same in her mind.  She does not want to be anti-aged.  She does want to get up and go at times, but it takes help.  Is that why we want to stay young?  Why are we working on keeping our appearance young, and not working on ways to stay independent in our daily routines?  Because if this anti-aging cream works, I will still need help getting to the bathroom!  Maybe we are working on that?  Maybe we need to work on that!  I also note that a lot of the ads say age reversal, wrinkle reversal, not anti-aging.  Maybe that is the new politically correct way to say stay young!