Yes it can be done! Not just on a scale of "anything worth thinking is possible" but because it's achievable and has been proven many times. The world is full of inspiring examples of great men and women that have had career change when it was thought that they were ready to retire or already retired.
You might have lived your life putting others before yourself, and going the paths of greater returns. Or you had so much on your plate and couldn't risk going with your dreams, there's nothing worse than unfulfilled potential. The saddest thing about choosing to be an observer is the fact that you never tried. Who knows if you could have been the best musician of your time?
Two useful examples
Judi Dench is one of the most revered actresses out there, though her name is now referred to a household. She wasn't in the movie industry 20 years ago. Judi was already in her 60's when her movie career took off. While she had a fruitful career in the U.K., her role as M in the Goldeneye movie has made her well-known in the U.S. and beyond.
Sanders (KFC) is probably the best example you are going to see in this category and one that gets to me about starting late. Colonel Sanders didn’t think of starting, he just knew he had retired and was tired of living and was ready to die. One day, he picked up a pen to write a suicide note but ended up defining his passion and decided on living at 65 years old. Now, he has one of the largest restaurant chains in the word and died a millionaire.
Age doesn’t define success
The story of Colonel Sanders, a man who was ready to die is one of the most inspiring. It will always convince us that careers can be achieved anytime, and age is not a barrier to dreams and passion. Seeing people who have succeeded at various careers late in life is the best reference to consult while understanding that age has nothing to do with success. You might feel stuck setting in new ways or scared of a change at this point in life. But where there's passion and a burning desire to fulfill your dreams there are lots of possibilities.
Are you working effectively but not getting the feeling of fulfillment? If you keep doing things you think everyone needs, it will all come down at you. Not the people you're using to establish standards for yourself. Do you feel it’s safer to remain where you are and not pursue your dreams because you're afraid of failure?
All you need is a lot of devotion and success model. Deal with the fear, don't compare yourself now and before, be realistic about what you want to achieve, be flexible, consider all your options and stay strong. Making a career change at an old age may not be as easy as it could have been, depending on the field. But it’s always better trying than never.