During the installation service of our new pastor this past weekend, the first reading was from Jeremiah 1:4-9. A part that particularly stood out to me was verses 6-9(ESV), "Then I said, 'Ah, Lord God! Behold, I do not know how to speak, for I am only a youth.' But the Lord said to me, Then the Lord put out his hand and touched my mouth. And the Lord said to me, 'Behold, I have put my words in your mouth.'"
From what I understand, we do not know exactly how old Jeremiah was when he says "I am only a youth." However, judging from the perceptions of the time, he could have been anywhere from his mid-teens to mid-twenties when God called him as a prophet. Let me type that again: he was the age of a high schooler to someone just completing college. Let me say that another way: he was in the age group of people that are thought to "know nothing" today.
Where am I going with this? You can probably see where I'm going, but I'm going to type it out anyway: you are never too young to make an impact for the Gospel. You are never too young for God to use your faith to change peoples' lives. Want to see proof of that? In Matthew 18:1-6, Jesus uses a little child to teach the disciples humility and about how we should approach faith, and in Matthew 19:13-14, He states that the "kingdom of heaven belongs to such as these" about children, teaching us we should have the sort of trusting faith that a child does.
Now some of you may be saying, "But Jeremiah was a prophet. They're a special sort of believer." Granted, Jeremiah was called for a specific purpose, but that does not mean you are not similarly called to reach others with the Gospel of Christ. At Pentecost, when the Holy Spirit descended on the Apostles as tongues of flame, Peter said this prophecy of Joel was fulfilled "In the last days it shall be, God declares, that I will pour out my Spirit on all flesh, and your sons and your daughters shall prophesy, and your young men shall see visions, and your old men shall dream dreams" (Acts 2:17). Just as God gave Jeremiah the ability to speak, so, too, God entered believers through the Holy Spirit in order that they would be empowered to speak the truth of Jesus to all people. And this Holy Spirit was not just given to the Apostles, for Peter goes on to say, "Repent and be baptized every one of you in the name of Jesus Christ for the forgiveness of your sins, and you will receive the gift of the Holy Spirit. For the promise is for you and for your children and for all who are far off, everyone whom the Lord our God calls to himself" (Acts 2:38-39).
Ultimately, the point I am making is this: as a Christian, God has called you to reach out to anyone in your life with the good news that God loved them so much that He sent his son, Jesus, to live a perfect human life and die a gruesome, human death, in order that when Jesus rose from the dead, He would ensure that all believers in Jesus would not be condemned for their failings, but would spend eternity in the presence of God. It doesn't matter what age you are. Don't be afraid. Let your life as a Christian speak the truth of Who God is to the people in your life. Trust that God will take your efforts, whatever they may be, and use them to change lives. After all, remember whose Spirit makes you able to speak: the Spirit of God. As the creator of language, He'll figure it out for you.