Let no man despise thy youth; but be thou an example of the believers, in word, in conversation, in charity, in spirit, in faith, in purity. (I Timothy 4:12 KJV)
What common Joseph, Daniel, and Jeremiah had in their days? Was it age when they become a prophet? This may be true. Joseph was cativated into Egyptian by his own brothers and later he became a general of Egyptian. Jeremiah began in his ministry when he was youth as a weeping prophet for his people. Daniel was in Babylon when his people were cativated there, but he served and worked with King Nebuchadnezzar. If you notice, three of them began to call for God's duty when they were young. Most of they may not have any clue what God would restore for them, except obeying His voice. As they were getting older, they began to understand what God had minded for them. Jeremiah 1:5 tells us that God knew each of them before they came out from their own mother's womb. He has purpose for each of them to give life. You and I have a greater purpose of being here. There are no mistakes about why God gives us life.
If you feel like nobody want to work with you because you are young, it is their problem and not yours. Although the world may seem more to become an adult world, God still can use you to reach the lost souls into His presence, just as He did to Joseph, Jeremiah, and Daniel.