"What is the one activity most important to you?" - Common Application

I would be very appreciated if somebody helps me correcting my grammar mistakes and any other awkward sentences. Thank you! =)

Description of the one activity most important to you and explain why.

"Welcome to ***** High School Concert choir." I still vividly remembered the day when I heard that warm greeting and a hug from my choir instructor.

I signed up for the intermediate choir in my freshman year in high school.
To be honest, I did not expect much about neither that class nor the quality of the choir because there was no requirement to be in intermediate choir.

Unlike what I expected, I enjoyed singing in intermediate choir very much and I started to wonder about how good would concert choir sound like. So I went to the annual holiday concert and I could not believe how amazing the concert choir sounded.

The concert choir members were only couple years older than intermediate choir members, however their attitudes toward the performance were absolutely mature and committed.

From that night when I watched concert choir's performances, I could not wait to be a part of concert choir. I worked and practiced harder in and out of the classroom and hoped to make it to the concert choir's audition the following school year.

Luckily, I made to concert choir right before the summer break of my freshman year and being a part of the concert choir has been the most important activity throughout my high school years.

Music has been one of the most important parts of my life since I was young and I have performed numbers of times within the church choirs and intermediate choir. However, when I first performed as a member of concert choir, I felt the best contentment which made me once again realize that the most beautiful instrument in the world is human voice and hard work always pays back with great satisfaction.

When I first went into the intermediate choir, I was just a shy and vulnerable student that nobody noticed, however as I learned how to express myself by putting my emotions into every piece that we sang, it helped me gaining interpersonal growth along with confidence and leadership. I became a section leader in my first year in concert choir, a vice president and a section leader in my second year and I was very fortunate to become a concert choir president in my senior year. From all those experiences within choir, I learned to become confident, outgoing and amiable by working in a great choir with hard-working and committed choir members and a great instructor. I can not stress enough how concert choir helped me to develop as a stronger and better person.

If this supposed to be a five paragraph essay I think you should divide it in to intro 3 body paragraphs and a conclusion.

Even though I don't know how to find errors on your essay
I learned a lot just by reading your essay.

I signed up for the intermediate choir in my freshman year of high school. To be honest, I did not expect much from either that class or the quality of the choir, because there was no requirement to be in intermediate choir.

Contrary to my expectations, I enjoyed singing in intermediate choir very much and I started to wonder about how good would concert choir sound like. So I went to the annual holiday concert and I could not believe how amazing the concert choir sounded. The concert choir members were only couple years older than intermediate choir members, but their attitudes toward the performance were absolutely mature and committed.

Music has been one of the most important parts of my life since I was young, and I have performed numbers of times within the church choirs and intermediate choir.

Nice job!