I have a friend who was diagnosed with breast cancer at the age of 78. She went through surgery, chemo and radiation. She is going strong now at 82.
MaryJ, when you are first diagnosed, no matter your age, the majority feel just like you. It is doable, just one day at a time. Seek support and help. Let others help you out. Don't be brave be grateful for all those who are willing to help you take the load. Trust the Doctors and Nurses. They really have your best interest at heart.
Check in here often. This site got me through a lot and they can do that for you too.