Everyone has a lot of dreams .Some people want to be rich.Some people want to be famous.（Some people want to be rich while others want to be famous）.I have a dream,too.When I was a small child（When I was a little kid）,I had a dream that one day I would become a great pianist.I will（would） play the piano in the Musikvereinin Vienna to（去掉to,改成and） make the best music for the whole world.When l was three years old,my parents help me please a teacher（my parents paid a teacher for teaching me playing the piano）.She is very beautiful and kind.She told me how to play the piano and how to make the music sound better.When l learned two months time（After learning about two months）,I thought play the piano very difficult（改成I thought it is very difficult to play the piano）.After learning my arms are very acid（去掉这句,改成 I felt my arms acid ）,but I did not give up.Now,I’m twelve years old.I still want to be a pianist.I did a lot for the dream（加上to be a pianist ）and I spend（改成spent） more than two hours playing the piano every day.It’s very hard,but I insist （加上on practicing ）it（去掉） for nine years.No mill,no meal.Now I（I’m） in the Grade Examination of musical level of current year for nonprofessionals（这句话我没懂你要表达什么,所以没改） and have reached the 9th.grade in the playing of Piano（如果你想表达的是：我现在已经达到钢琴九级的话应该这么写and have reached the qualification for the grade nine in piano-playing）.Piano is a kind of music（这句话你要表达什么呢?没懂,但你的表达方式肯定不对.）.It helps me learn something of （of 改成about）music.Become a piano play is a hard job（Become a piano player is hard）.I will be harder and harder to practice it（I would practice it harder and harder） .I believe I can do it.
你后面写的有些表达不清,不能确定你要表达什么.