A juvenile question>

The concept of a jury of a person's "peers" is one of the few key aspects of English law that didn't become part of our country's law after independence.  The reason for this is that we have no "peers," everyone has equal status before the law.  Unlike England, we have no aristocracy (dukes, earls, etc.);  the right to a jury of one's peers, in England, means that a nobleman accused of a crime has a right to be tried by a jury only of other nobles, and sometimes the entire House of Lords acts as the jury in these cases.

The jury for a criminal trial of a person under 18, being tried as an adult, will be drawn from the same jury pool as any other criminal trial at that courthouse.