Could you correct my essay?

He taught us not only about music, but also attitude. For example, he said to students, “be punctual, and being proactive.” When we couldn’t do that, he even said “get out!” At first, I was afraid of him. However, I was gradually attracted by him. I thought wondered about the reason he was so strict to students. Then, I noticed that it was for us. He faced students and music seriously and really wanted us to do the best. I felt his passion for music and students. I rethought myself (意味が分かりません。ごめなさい。）. Consequently, I found that I always avoided many problems when I ran into them. I knew how lazy and weak I was. Then, I tried to achieve what he said, not only for the concert, but also for my life. My life has changed since that time, and it has been more exciting. Therefore, I want to be a teacher who can make someone get serious like he did. Mr. Naito is still working as a high school teacher, and I’m a university student, but, even now, we keep in touch.