Congratulations - and I pray your heart will be like mine has been these past few months: filled with gratitude and thanksgiving to God for all His blessings to you. The Bible says, "Give thanks in all circumstances" (1 Thessalonians 5:18).
I never dreamed I would live this long - but God had other plans, and my sole desire is to use whatever time He gives me for His glory. No, I can't do everything I once did, and neither can you. But I've found that God has given me other opportunities - the opportunity to spend more time in prayer, for example, or to devote more time to my grandchildren and great-grandchildren. Hopefully they will see the importance of living for Christ as the years go by.
This doesn't mean that old age is easy - for it isn't. Our bodies wear out, and it's easy to become preoccupied with our health or other immediate concerns. Old age can bring us loneliness or grief also. But if we know Christ, we know we are never alone - and ahead of us is heaven. God's promise is true: "Even to your old age and gray hairs I am he, I am he who will sustain you. I have made you and I will carry you" (Isaiah 46:4).
Thank God for every day He gives you, and ask Him to help you live it for His glory. But most of all, keep your eyes on the future, and on the hope we have of heaven because of Christ's death and resurrection for us. Is your hope and trust in Him?