Check out the following websites, and then call an experienced MN defense lawyer with any specific questions. Good luck.
DISCLAIMER: I do not practice law in your State. This answer is provided for informational purposes only. This answer does not constitute legal advice, create an attorney-client relationship, or constitute attorney advertising.
A person who is charged with a crime, where probable cause has been found can petition the court for an expungment of public government records under Minnesota Statutes Chapter 609A, if their case was (1) juvenile certified as an adult; (2) certain 1st time drug cases; or (3) others where the case was resolve din favor of the accused, which courts have interpreted to mean no guilty plea and no conviction. If you plead guilty, then perhaps the statute won't help you.
I'm not sure how a guilty plea with six months probation could end up being a petty misdmemeanor, but if the judge said that, it would probably be worth the effort to confirm that has been done on your court record, and perhaps seek a court order from that judge accordingly. There might be a way to clean up your record some, but it will not be simple or easy - because you plead guilty. See links below FFI: