One possible version

I still remember how nervous I was on my first day in the new school three years ago, when I found it difficult to follow my teacher in the first English class. The teacher spoke English throughout the class, which was totally different from the lessons I had taken before.

In the morning class the next day, the English teacher came to me while I was reading the text aloud as other students. After listening to me for a while, she gave me a big smile and said she liked my voice very much. The smile shone on the whole day and the following days. A week later, I voulunteered to take charge of English study in my class.

Thanks to the comforting smile in my first morning class, I began to be confident.