He may be wondering where he’s sitting, which of his friends may be in the class, if the teacher is nice or not, if he left any supplies at home, the list goes on and on.
Well they could be thinking of anything to be honest but typically a child will have thoughts of fear like: "will my teacher like me?" "what are the students here like?" "i wonder if i can fit in with the rest of the school" or anything similar to these thoughts
