Beata and Fior,

I like the way you divided this into two parts, one telling her history and the other detailing her present and future prospects. That works well.

-The first sentence should be "Yuja Wang is a pianist."

-Youtube is the name of something, so you shouldn't put "the" before it, as you wouldn't say, "Our teacher is the Kevin."

Otherwise, there are no errors at all, just well-composed sentences.

•  Is pianist. She started tinkering with the instrument when she was about 6. Her first concert was at the age of 7, when her feet still dangled from the chair. Her earliest public performances took place in China, Australia and Germany. All of her childhood performances are on the YouTube. When she was 18, she had carved out an interesting niche for herself  as a kind of pinch hitter. 

 
• Now at 22, Wang is heading a project of her own: Her debut CD, "Sonatas and Etudes", has been nominated for a Grammy. The future looks promising for this 22-years old. She loves music and presents herself as a serious musician.