If you are 17 and is sent to juvenile for fighting and breaking the victims arm what happens?

sit in jail til the judge can see you then he will probably get charged with aggravated assult

Another View: There is no way to answer this question knowledgeably. It is all up to the ruling of the juvenile judge you will see. A lot depends on the situation - your past record (if any), and the circumstances of your breaking the arm. You are old enough that you could be bound over for trial as an adult if the judge believes that the assault and arm-breaking was vicious enough or done with pre-meditation.