Fear is such a powerful weapon for the enemy.
The sooner we realize that fear has no dominion over us, the sooner we can truly become who God has made us to be.
Personally, I struggle with fear all the time. I read books, watch movies, and witness people do things that I immediately tell myself I would never be able to do. But this is not the way God made me to think. Gods love for us, just the way we are, is a power source that, once we tap into, can destroy all the fears that we may have.
I want to encourage you, and honestly myself, to realize that no matter what it is that we may look at as impossible, God looks at as possible, and that if God is leading you to something that scares you, whether it be a huge change like moving to a third world country, or something simple like talking to the kid you sit next to in Biology about Jesus, I pray that you remember that God is living in you. He is empowering you to do His will in ALL things, not just the big things.