The Prophet Jeremiah told us

Before I formed thee in the womb, I knew thee, and before thou camest out of the womb, I sanctified thee, and ordained thee to be a Prophet unto the [h]nations.

6 Then said I, [i]Oh, Lord God, behold, I cannot speak, for I am a child.

7 But the Lord said unto me, Say not, I am a child: for thou shalt go to all that I shall send thee, and whatsoever I command thee, shalt thou speak.