The Queen will not be attending part of installation ceremony for knights of the Order of the Bath at Westminster Abbey because of the steep steps she would have to negotiate:
http://www.telegraph.co.uk/news/uknews/queen-elizabeth-II/10818951/Queen-drops-out-of-ceremonial-role-over-concerns-about-steep-steps.html
In the story above, there's the following passage:
"Buckingham Palace announced two years ago that the Queen was giving up long-haul travel as a concession to her age, but otherwise the Palace has repeatedly insisted the Queen is not scaling back her workload."
I'm no royalist and neither am I an anti-royalist. To me, the royal family are a bit like McVities Digestives. I don't find them particularly exciting, but I really wouldn't be happy to see them go.
But I'm thinking...why should an 88 year old woman carry on with duties that she performed when she was a 44 year old woman?
It might be her choice, but at the end of the day, if it were your grandmother, wouldn't you say, "No Liz...enough. Put your feet up, and watch the races."