Could an elderly person extend their life from sheer determination or spite?

I have in mind Her Majesty, the Queen.
She was frustrated with her son’s dalliances with his now wife. Harry has made a break for it, and he has in past stated that none really wish to take the throne.
I wish Her Majesty so long a life as she desires. I feel she has shown a lot of class at times even when others would tear their hair and scream. She is, however, quite getting on in years, and there seems no stopping her. Could she be determined to keep the crown until such time as one of her great grandchildren might prove suited?