The prosecutor has two years from the offense date to charge you. You can avoid the initial court appearance (arraignment) if you hire an attorney (the attorney can waive arraignment), but you can't avoid going to court all together.
You should never speak to the prosecutor on your own. Even a seemingly innocent statement can be viewed as a confession. You can look on the Washington State Courts website to see if charges have been filed against you at http://dw.courts.wa.gov/index.cfm?fa=home.home . You should consult with an attorney in your area to discuss your options. You will almost certainly have to make one or more court appearances. I see that you listed the case as Juvenile. That could make a big difference in the way the matter is handled. If you haven't done so already, you should probably tell your parents about this. If you are old enough to go get in trouble, then you are old enough to face your parents and ask for their guidance as well. They will be upset, but they would probably rather hear about this from you, instead of hearing about it from the police or courts. At a minimum, call a few criminal defense attorneys in your area. Most of them will give you an initial consultation for free.
Theft 3rd degree is what you are talking about and that is a gross misdemeanor. The State has 2 years to file the charge against you. Payment of the civil penalty has no bearing on the criminal charge or whether or not the State will charge you or not. You should have consulted a criminal defense attorney before you paid anything because that is an amount of money that isn't required and it could have been used as a bargining chip in the criminal world by now it has already been done so that is that. Do not talk to the prosecutor on your own, for any reason because what you tell them can and will be used against you in court. What you say to your ATTORNEY is confidential. Good luck and get an attorney.