I sometime wonder what is wrong with people who mistakenly think USCIS (or American govt.) is so stupid that they wouldn't know anything if it's not told to them...
Let me be very clear here- OP has deliberately/wilfully and knowingly concealed his arrest/offense/conviction on his citizenship application despite of the fact that the application itself clearly states about disclosing ALL the arrest/conviction/crime/citations. Let me remind readers, OP received a fine for $200, whether for 'pretty" offense or citation, yet still it was a citation. Then how come OP forgot to mention about it when application asks to disclose all the citations as well. It wasn't a traffic ticket citation so to have any argument/discussion or second thought on it.
It didn't bother OP even a bit until only now when he received a letter from USCIS mentioning about the arrest. Even in my wildest dream, I refuse to believe that OP didn't remember about it, or mistakenly forgot to disclose about it, or thought it wasn't an arrest/conviction/crime; rather I strongly believe without a doubt that OP mistakenly undermined USCIS and thought US govt. would never find out about it, but he knew all along what and why he is hiding that fact on the application. Hmmmm..OP miracleously/magically remembers NOW the WHOLE INCIDENT crystal clearly all of sudden but only AFTER receiving the letter from USCIS!!!! Give me a break, will ya???
No offense/insult, but how stupid one could be in thinking that an arrest wouldn't show up on background checks regardless of it's disclosed or not on the application?? I mean it's not a rocket science to know a simple fact that the sole purpose for govt. to do all kinds of background checks on applicants is just to find out any criminal history on them regardless of what applicants have mentioned/disclosed on their application. Did OP think USCIS wouldn't know about it if he wouldn't tell/disclose it on the application?? So much for the common sense...
It was such a bad judgement on OP part (probably because of stupidity/ignorance/or thinking being oversmart) when OP thought it was more important to him to visit outside the US (even if there was a compelling reason) than clearing off the criminal matter first unless OP didn't care his immigration life in this country. Just know that people get arrested and serving time in jail everyday around the world even though they have family or medical emergency. So, bringing about family emergency doesn't cut off the fact of being a criminal mess which could take you away from family and loved ones for a long time, or could minimize the chances of family to have financially getting taking care of in case one is deported from here if s/he is making good money.
By the way, courts never set up a date for the trial right away; rather trial is actually scheduled a way long after (many months later) since laws give the time to both parties (prosecutors and defense) to gather evidences/witnesses for the best presentation of their case. Besides, most courts are so busy to schedule a trial date right away. Thus, they don't give a trial date before many months later of the incident. And even if a trial is set up, any party in the action can request to reschedule it for another time if there is an emergency or a reasonable reason. In a criminal case, defense attorney can file a motion to the court to put the matter on calendar for another date. I believe, you were so keen to go to your country, or didn't want to spend money on attorney to defend yourself against that you thought that paying the fine and pleading guilty is the easiest way to walk away from that criminal matter. But now when that arrest/pleading has come back to haunt you, you are now talking about it.
Does OP not know that he could have been denied and still could deny an entry into the US upon coming from the oversees depending upon the officer at the port of entry if his crime/conviction falls in a deportable offense?? Just because it hasn't been the case so far, that doesn't mean it cannot happen in the future. It just depends on the officer at the port of entry.
Keep it in mind, a theft offense is crime of moral turpitude, and very much a deportable offense depending on the criminal statute of PA where the crime was committed/occured. So, don't jump on the conclusion too fast in thinking that it's a "pretty" offense even if you are told so by attorneys. Don't always believe what most immigration attorneys tell you on anything because they don't always tell the whole truth even if you pay them a big chunk of money; rather most of them practice immigration laws only on papers like filing cases and appeals than going in the court and dealing the matters in front of immigration judges. Besides, most of them don't know much about a specific area of immigration laws even though they are immigration attorneys. Their speciality is limited. Most of the time attorneys purposely mislead people to scare them so that they could be retained.
OP now must obtain a certified copy of court disposition of his case. Also, try to obtain police report and any other court documents. He must be sure to show all this to a good immigration attorney (not to any "John Doe" attorney). Attorney will need to research PA criminal statues on a theft offense, and the attorney will also need to review all the court papers to see what you plead to evaluate whether you will be facing a deportation or not based upon all these factors. If it would seem that you would be facing a deportation, then attorney may advise you to do something to vacate that judgement to avoid the deportation, only if you would pursue for it and only if attorney knows how to prevent deportation in this kind of situation.
And you should also know that immigration officer might very well deny your citizenship application, not because of what you did/plead/convicted for; rather for not being truthful on the application about it by not disclosing it. Lying and concealing a material fact is same as misrepresenting yourself which a ground in itself to deny the application even if your application is approvable otherwise. Another biggest problem here is that you didn't mention about it at your green card application as well which means you concealed a material fact under penalty of perjury and misrepresented during the green card interview to the officer by not disclosing it under oath, which is a crime in itself and a ground to deny the benefit and a lifetime bar to the entry into the US. Now the matter is VERY-VERY serious here, not because of your offense to being a "pretty' offense, a moral turpitude offense and for not disclosing it on citizenship application; rather it is for not disclosing on the green card application especially when it's and was a material fact. Get a good attorney soon.