I am also in my middle 80's and enjoy life. Avoid stress, don't celebrate birthdays as they are just a way of making you feel old.
Also don't concentrate on the negatives and keep positive. Do good
and keep busy. Volunteer and remember there are some who will treat you like your old and don't think you are still "use able". Disregard these idiots and remember they will be older and will then get religion. Net: Don't worry just take each day as a gift.