Is this theft charge going to affect me for my citizenship?

The immigration-related ramifications of criminal matters is among the most complex areas of immigration law. In some instances the USCIS may treat a misdemeanor as a felony and may treat a case dismissal as a conviction (that generally happens when a dismissal follows acknowledgement of the elements of an offense as part of a pre-trial diversion or similar process). In any event, it will be necessary to disclose the arrest and provide court-certified copies of a full set of disposition documents (or proper evidence that no such documents still exist). Especially since a theft offense can have very harsh immigration-related consequences, it would be a mistake to proceed with a naturalization case without consultation with an immigration attorney who, after learning all of the relevant information and seeing the court disposition documents, could advise about eligibilities, options and strategies to attain your goals, and who then could offer legal representation in the often complex application process.