At this point, God provided me with closer relationships with the few friends whose major strength is to do just that. God has given much to me through this. First, giving myself to others is the same as giving my skills and abilities to others - a joy because it is from and for God. Second, it has allowed me the boldness to speak to others about my faith that I could not before, as we are commanded to do in Matthew 28:19-20.
Therefore go and make disciples of all nations, baptizing them in the name of the Father, and of the Son and of the Holy Spirit, and teaching them to obey everything I have commanded you. And surely I am with you always, to the very end of the age.
I am still an introvert, as I always will be - my mental strength is renewed only in my time apart from people. Now, though, my joy is increased when I am among those who are, or may one day be members of the family of God.
If you fear the times when you must speak to others, or are even unsure that you can do it, keep in mind that this is part of God's plan for all of us. God will prepare a way for you to do so.