今までのあなたの人生の中で最もexcitingだったことかsadだったことを書きなさい。

I had been learned playing the piano.
When I was a elementary school's children,I appeared on a piano competition with my sister.
I was very nervous at that time,but my sister encouraged me.
So we could enjoy playing the piano,and we could have very nice perfomance.
In addition,to be surprised,we got first prize in the competition.
I was very exciting,and tears ran down my face.
It became most exciting event in my life.

この英作文の添削してほしいです＞＜！