根据短文内容，判断正误。
I used to be an active girl. But two years ago, an English speaking competition held in my school changed me a lot.
I stood on the stage(讲台) for the first time. I was so nervous that my brain(大脑) suddenly became empty. Not long after I began my speech, the hall turned noisy. It seemed that they were laughing at me. I knew I failed.
From then on, I became quiet and always stayed alone. I didn't want to express my ideas in public, even in class. Every time I wanted to say something, I thought people would laugh at me. My friends couldn't understand me, and they left me, one by one.
One day, my science teacher asked us why trees in forests were much taller than those in the wild. "Ha, what a silly question!" I thought.
"There's not enough space in the woods for trees to expand their branches. Of course they have to grow taller than others. The trees in the wild needn't do that since there's enough space. " I said in a low voice.
To my surprise, the teacher said, "Yes, you're right. It is a competition. " My face turned red right now. I hadn't spoken for a long time, especially in public.
Then the teacher explained how tree s in forests had to grow taller to receive more sunlight. If not, they would die. This also happened in our society.
What's more, the tree that doesn't live in a crowd is just like a person who has no friends in life.
I raised my head slowly and found the teacher was looking at me. His eyes were as warm as sunshine. I realized that I must stand up and face the truth.