Although I am not familiar with the laws in Indiana dealing with juvenile offenders, generally speaking your file in Indiana should be sealed and not be viewable by the public.  Keep in mind that certain governmental agencies may access your records, especially if you are arrested for a new offense. 

In Arizona there is no way to get your record expunged, or completely erased.  Unfortunately there will always be a record of the conviction somewhere, and it could be accessed years from now.  If you are concerned about future employers, most only inquire about whether or not you have been convicted of a felony as an adult, however, be sure you read the application closely.  Since it happened when you were twelve, many employers may overlook it, or may simply want more information about the details of your arrest before deciding whether or not to hire you.