I was really successful with everything I got involved in music-wise.
"...I was successful in every music related activity..."
It's more concise this way, and the word "really" is unnecessary.
I tried to hide my hurt
Replace "hurt" with "pain"
I like how you transition from your nervous about the audition to after the auditions being over. It sparked my curiosity.
This essay is good, but is it strong? It can be if you condense your essay and try to show yourself as strong because in the end, you showed yourself as weak and nervous, but later delighted. Focus more on showing yourself as strong and determined to conquer the challenge.
Good Luck with MIT!
And can you give my common app - extracurricular essay a read?