OP..
I believe that people should

forward to getting older. Being middle aged or senior aged isn't as bad as some may believe.
There are plenty of older people living their best lives, travelling, spending time with their families, etc.
It just depends on the person and the type of lifestyle they chose to live...
Life is what one makes of it. If health is a concern for some people, then they know that they have to eat right, not engage in unhealthy vices and exercise.
If relationships is important, then people know what they need to do in order to get the type of relationship they desire.
No big deal!
I believe that some younger adults are afraid of getting older because they may know older loved ones who may be suffering....
Although they may be the case for many older people, it isn't the case for all, so I say live your life as best you can!
It's a given that everyone will meet their demise at some point. Can't worry about that day until that day comes. In the meantime, live life and have fun!
.*shrugs*