Increasingly, mid-life means anything from our late-40s upwards. As our life expectation increases all the time, so 'elderly' is getting set back further and further. And in any case, it's still true that you're as old as you feel. Many nono-genarians (90+) lead productive, healthy, active lives.
If you're 50 right now, you're likely to have at least another 35 years of active, productive life.
Divorce rates for men and women aged over 50 are increasing (against the overall trend for all ages which is declining)
In the UK, more than 3 million people (about 5% of the population) live alone
In the UK, almost half the population is over 50
Almost a third of all people made redundant are over 50
Reaching a pensionable age is less and less likely to equate with 'retiring'.
There are few, if any, jobs-for-life these days. The world is increasingly needing us to learn new skills, regularly. This is true both personally and professionally.
Just because you've trained to be A Something, it doesn't mean you need to be (or are able to be) A Something for your whole working life. You can be Another Thing or even Several Different Things At The Same Time.
You laid the foundations of the life you're leading now many years ago, by making the particular choices you made.
Foundations can be re-laid.
On the other hand, there is great power in the momentum created by consistency.
The best kind of work to do is the work that you're good at. This may or may not be what you love to do.
You know what you're good at now, much better than when you were 'young'.
If you believe in any kind of 'after-life', then what you do NOW is absolutely crucial.
A large amount of personal income doesn't create happiness. In fact, there's plenty of evidence to suggest that it's more likely to achieve precisely the opposite.
It's good to follow your heart. But make sure you know what your heart is first, or you could get into a mess.
The greatest and most important learning of all is about yourself. Your Self. The more you know about You then the more your choices - in love, work and life - will be constructive and positive.