Undergraduate / Debate Team; Common App Short Answer (extracurricular) [4]

Hi everyone!
I would gladly appreciate your help in reading and checking through my transfer application work.
The topic is "Please briefly elaborate on one of your extracurricular activities or work experiences".
I not a native speaker,so I need advice on both sentence corrections and the thought.
Thanks everyone!
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In the first year of high school, I was a good writer but still froze when it came to articulation; abashed and non-confrontational. I set out to change it and then joint debate team. During the first stimulations, I remember being so nervous that I couldn't really think straight even with notes gripped in my hand. It was mortifying, almost torn me down, but I stayed with it.

Gradually, I was shocked that my silence in all classes has been completely destructed; my innocent partiality of our country's government was totally destroyed by debating about conflicting issues like the Tibetan; due to no long self-effacing, my role in other activities became more important.

Debate re-created me.
When felt disappointed with the current university and even frustrated, I entered debate team of department. Debate raised me up again by motivating me regain the confidence of convincing people and speaking challenging words out loud. And it was in there that I found one of my like-minded partners, with whom I co-founder the independent student magazine later.

Maybe I wasn't known as the best debater, but I'll always be grateful for what it has done to me.