Josh:
    I don't know the statue for "Careless Driving" in your state, but I would have to guess that there might be some discretion on the part of the officer. If you were not following the letter of the law on your permit, then you were driving carelessly.  There is a reason that the permit is restricted and if you go outside of those restrictions, you are acting "carelessly" according to the law.  Hope that makes sense.
   In your situation, I think it would be a huge mistake for you to try to argue against the Careless Driving charge unless you know what legally justifies the charge and your situation does not meet that burden.  
  You're a smart kid who made a mistake.  I totally agree with the advice given to dress respectfully, (remove any facial piercings for the time if you have any), remember your manners, look up at the judge and say as little as possible and NEVER disagree with him or her.  Do not take a cell phone or newspaper or book into court.    Be respectful, show remorse and explain, succinctly, what you learned.  I would also consider offering, if it is true, that your parents will expect you to somehow repay the $500 deductible and any fine that applies and how you will be doing that....extra chores, selling something that is valuable to you, taking a job...whatever.  You want to show that you ARE responsible. 
   Usually, Judges are not out to make examples of kids who come to court with good qualities: respect, remorse, responsibility.  
   Practice what you might say, again, succinctly, if they judge ASKS you WHY you did it, did you know it was wrong, what have you learned from this experience.....
   Good luck.  EVERYONE makes mistakes.  Not everyone benefits from the experience by being responsible for their actions and learning the lessons.  
   Here in Long Island, we had a high school kid in a car with four friends, speeding back to school from lunch.  The driver lost control and hit a mini van with a woman and her disabled child.  The driver lived, but many of the others did not.  His future is totally ruined.  He had a prior accident just weeks earlier.  Obviously, he didn't learn from the first incident.  
    Hopefully, you will benefit from this experience and it will serve you well in the future!  Please let us know how you do, Josh.  I'll be praying for you.
Nancy