it'll all depend on the juvenile court judge's opinion of what will straighten up your son; at least that's my guess.
Not knowing anything about your location nor the j.v. judges there, you could have any kind of judge at all -- harsh, soft, fatherly, bleeding, etc.
Still, I'd say that $60 value isn't much of a 'felony'.
"Uttering a forged document" is usually a crime in which hundreds or thousands of dollars are stolen by counterfeiting (for example) payroll checks or Cashier's Checks [a currently popular scam].
Threatening a 14 year old with "uttering" and a felony charge is most likely bluster on the part of the officer. I can't see a j.v. judge jailing a 14 year old for that when s/he knows that the j.v. slammer is full of violent criminals and drug sellers.
Alas, judges have been harsh before and seemingly without reason.
When you find out which judge will hear the case, ask around the courthouse about her/his reputation. If it isn't "hang 'em high", I think I'd be inclined to forego hiring an attorney and just make a deal with the State's Attorney to plead guilty to a non-felony charge. [Talk with them in advance about it.]
Assuming, of course, that your son actually is remorseful and will be seen that way in court. [Stone faced stoicism likely won't go over well.]