God has given this opportunity to you, and I hope you'll see it that way -- not as a burden but as an opportunity. In other words, don't spend time worrying about what others might think of you, but see this as an opportunity to help someone who might be discouraged or confused.
How can you make your words helpful? First, base them on the Bible. You might, for example, take a few verses from one of the Psalms (such as Psalm 27 or Psalm 119), or even one of the brief Psalms (such as Psalm 1), and read them to the group. Then take a few minutes to expand on them and make clear to the group what those verses say.
As you prepare, study those verses carefully, and ask yourself what difference they should make in your own life. Then go a step further, by asking what difference they should make in the lives of your listeners. In other words, don't just repeat what the verses say, but show what difference they should make in our lives. Remember: The Bible is God's Word, given to us to change us and make us more like Christ.
Pray as you prepare your devotion. Pray not only that you'll do a good job and that God will help you make His Word clear, but also that He will use it to bring others closer to Himself. Remember the Psalmist's words: "The unfolding of your words gives light" (Psalm 119:130).