Are you concerned that being old would mean no more work for GOD? Don’t be. As long as you still have breadth and strength, serve our FATHER and go where or do what HE asks. Look at Moses, Aaron, Abraham, Caleb, Sarah and so on. Don’t discount yourself at old age or think you can no longer contribute to the work of GOD. Keep at it for as long as you are able.
Exodus 7:6-7 Then Moses and Aaron did so; just as the Lord commanded them, so they did. And Moses was eighty years old and Aaron eighty-three years old when they spoke to Pharaoh.
https://bible.com/bible/114/exo.7.6-7.NKJV
Joshua 14:10-12 And now, behold, the Lord has kept me alive, as He said, these forty-five years, ever since the Lord spoke this word to Moses while Israel wandered in the wilderness; and now, here I am this day, eighty-five years old. As yet I am as strong this day as on the day that Moses sent me; just as my strength was then, so now is my strength for war, both for going out and for coming in. Now therefore, give me this mountain of which the Lord spoke in that day; for you heard in that day how the Anakim were there, and that the cities were great and fortified. It may be that the Lord will be with me, and I shall be able to drive them out as the Lord said.”
https://bible.com/bible/114/jos.14.10-12.NKJV
Psalms 71:18 Now also when I am old and grayheaded, O God, do not forsake me, Until I declare Your strength to this generation, Your power to everyone who is to come.
https://bible.com/bible/114/psa.71.18.NKJV
Psalms 92:12-15 The righteous shall flourish like a palm tree, He shall grow like a cedar in Lebanon. Those who are planted in the house of the Lord Shall flourish in the courts of our God. They shall still bear fruit in old age; They shall be fresh and flourishing, To declare that the Lord is upright; He is my rock, and there is no unrighteousness in Him.
https://bible.com/bible/114/psa.92.12-15.NKJV