I need to know the answer to ?

Question

"I became what i am today at the age of twelve."

What exactly is Amir referring to?

From the book, The Kite Runner

Answer 1

I think it was after he hid while his best friend Hassan was being brutally raped by Assef.  Amir witnessed the assault, but did nothing to help Hassan as he was too scared.  He then later sets up Hassan as a thief to drive him away, as Amir feels deeply ashamed over his inability to help Hassan.

Amir then comes back to Afghanistan years latter to try & find Hassan, in an attempt to make it up to him.  He realizes he was carrying the guilt for so many years.  But Hassan is no longer alive, only his son.  And I 'll let you read the rest.