Hi Jan
I am somewhat late in replying to your post so hope you read my bit of my history.
In 2006 (age 75) I had a hip joint replacement and 6 months later spent 2 months trekking the Himalaya.
In 2008 I had a heart valve replacement.
In 2010 (age 79) I walked my first camino from St Jean to Finisterre
In 2011 I walked from Oloron in France to Santiago (about 925km)
In 2013 attempted the VDLP but found it too hard for me so went to Pamplona and walked to Santiago, then walked the Camino Portuguese from Porto (total about 1300km) and celebrated my 82nd birthday with a huge chocolate cake sufficient for 32 helpings at an albergue in Portugal.
In 2015 (age 85) worked as a hospitalero in Estella and walked 300kms on the
Camino Frances.
I am not unusual. Age is only a number.
Next year I hope to return to walk more and be a hospitalero
Oh and more. I never have health insurance because I cannot get it. I have never needed medical attention, and my children have enough money in my will should I die to cover my repatriation. I have never planned my stages - just walk until I am tired but not too tired. I never book and always get a bed. I have never had a blister or other feet problems. I cannot imagine a better way to go from this world than on the Camino.
Jan - I hope you are convinced that you can go and have a wonderful time.
David