First, the fact that you've never been in trouble before would probably mean no jail time. So, I think it would be better to show up at the hearing and explain your situation to the Judge or Hearing Officer. Second, not showing up to Court for a hearing will propmpt an arrest warrant for Failure to Appear. If you're arrested on that charge then they simply won't hold you in jail until your 18 and then release you. You'll be held in jail until you appear before the Court and explain your absence from the previous legal matter. So, my advice is to show up for your hearing deal with the consequeces of your decision and but it behind you. Much better to have legal problems behind you than lurking ahead of you.
And while I'm dispensing free advice, let me give you some more. GET BACK IN SCHOOL! You are obviously smart enough to use the internet to do legal research so I would think you are clearly smart enough to finish school. You may not enjoy some of the class work or think you can do it, but you can. Don't worry about the fact that some classes may be harder for you than others, this is true for everybody.
Knowledge is the key to success. The more you know, the more opportunities for success you will have. Put this legal matter behind you and please consider getting back in school. You will never regret it. Do your best and let the Lord do the rest. Good luck.