If we looked only at the headlines every day, we would have reason to be pessimistic, because you're right: Our problems seem to be getting greater.
But don't forget two very important truths. First, the future is in God's hands, and nothing takes Him by surprise. He is sovereign, and behind the scenes He is still at work to accomplish His purposes. The Bible reminds us that "The Lord reigns forever" (Psalm 146:10). Even when the future seems dark, we can turn to God and trust the future (and our lives) into His hands.
Yes, Satan is also at work, and sometimes it looks as if he might win. But he won't! His power is limited, and some day Christ will come again to destroy all evil. Satan is real, and we need to take his deceptive schemes seriously–but Christ is just as real, and some day "he will reign for ever and ever" (Revelation 11:15).
Second, never forget that even when the future is unclear, God is with us and helps us when we know Christ. The Apostle Paul faced great danger and uncertainty, but he could still say, "I can do everything through him who gives me strength" (Philippians 4:13). No matter what the future holds, we do not face it alone if we know Christ.
Is your confidence in Him? And are you praying for your grandchildren, and urging them to live for Christ as well? It could be your greatest legacy.