The most important thing you can do right now is to be the best possible teacher you can be for this group. Don't think of it as something unimportant or second best; it could be the most important thing you ever do.
Why do I say this? One reason is because most people make their decision for (or against) Christ while they are still young. The older we get, the more set we become in our ways and the less likely we are to turn to Christ if we haven't already done so. The writer of Ecclesiastes urged, "Remember your Creator in the days of your youth, before the days of trouble come" (Ecclesiastes 12:1).
Pray regularly for those who are in your class, that God will give them a hunger for Christ. Pray also for yourself, that God will help you become an interesting and capable teacher. If you have never taught before, ask other teachers for advice. Think as well of ways you can communicate more effectively (e.g., by listening to them as well as talking). Ask God also to help you be an example to them of what it means to follow Christ.
Yes, someday God may open up new opportunities for you. But in the meantime, be faithful to what He has already called you to do. You won't always know what impact you are having but God knows, and He will reward you for your faithfulness.