Undergraduate / Speech & Debate - Common App EC's Short Essay [3]

Here's what I have so far:

Participating in the Speech and Debate team has been a major part of my high school life. Constant practices transformed me into a much more confident public speaker. With individual events, I discovered the opportunity to incorporate my love for writing. Often times I enjoyed the freedom to express my opinions and persuade my audience. The responsibilities that came along with the leadership position of event captain also contributed much to my personal growth. I was to run weekly practices and help respective event members improve their scripts. The most challenging part was to motivate and discipline the group as a whole, especially when everyone was caught up with schoolwork and other activities. There were times when arguments ensued and I had to keep peace. Through experiences, I learned to keep a positive attitude, remain calm under pressure, and work ahead of everyone else to set a good example. (149 words)

I feel like it's very vague without much content matter. Is this a good topic for the essay? Is there any way I can improve this?

I also have have other extracurricular activities, such as choir and church fellowship. I don't want to do choir because I have other supplement essays already focusing on music (I'm majoring in music). As for church, it seems too broad for 150 words.

Any help would be appreciated!