Queen Elizabeth II Turns 90 in 2016

I suppose she thinks Charles is unfit for the job, so she's decided to hang on as long as possible to limit the damage he can do by making his reign shorter, and hopefully grow up a little as the years go by.
 
I suppose she thinks Charles is unfit for the job, so she's decided to hang on as long as possible to limit the damage he can do by making his reign shorter, and hopefully grow up a little as the years go by.

I think it's probably more that she thinks she's been chosen by fate/God for this role and should stay with it as long as she is able. Few monarchs retire.