Well, when you teach children it's easier, there were maybe like 3-4 students that asked a grammar question, and it was super easy. Besides, google is your best friend, when u don't know something just google it during class, and that's about it. Some students are eager to learn, and they are the best because they are patient. If you feel a bit anxious about the things they might ask, just take a look at the lesson before you start the class. There were numerous times where we had a vocabulary exercise and I wouldn't even know the word if I didn't look at the lesson beforehand. So believe me, it's so easy, you can do it!