Whoever first said it was right: Old age isn't for sissies. No matter who we are or how healthy we've been, if we live long enough the infirmities of old age will catch up with us.
That's why the best time to prepare for old age is before it arrives, not after it overwhelms us. And the best preparation isn't just saving enough money or having good medical insurance (helpful as these may be). Instead, the most important thing we can do to prepare for our latter years is to build our lives right now on a solid spiritual foundation -- a foundation that only comes from faith in God, and faith in Jesus Christ as our Savior. If you have never put your life into His hands, I urge you to do so today. The Bible says, "Remember your Creator... before the days of trouble come" (Ecclesiastes 12:1).
Instead of being angry at God, learn to thank Him that He still loves you, and He is with you every moment of the day. God's promise is for you: "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).
In addition, ask God to show you ways to serve Him right where you are. Pray regularly for those around you, and encourage them both by your friendship and your words, as you point them to the hope we can have of heaven because of Jesus Christ.