unless removed by expungement or pardon, most states keep criminal arrest and conviction information on your record permanently -n for both felony and misdemeanors. Many states have a way to clear your record but a process is involved and it takes time.
Consult with a clemency/expungement experienced attorney in your area regarding this, it might be easier than I'm stating here but there's no way to know until you consult with someone that knows what the process involves.
If you were not taken to jail or fingerprinted it may not show at all on an FBI type criminal history report. Only on the clerk of court's record. If you did not do a shoplifting diversion, adult offender or deferred sentence type arrangement to avoid the conviction or expunge the case then the clerks record will be there forever. You can look online and search for records going back 15+ years.
It will stay on forever unless you get a deferred judgment expungement. Even if it is dismissed due to a deal involving a class or diversion program the charge with stay on Iowa Courts online forever with a note that it was dismissed. Even if you secure a win at trial it will still be a matter of public record for life. This is why many people seek deferred judgments even if they think they are not guilty.
I agree with the others answering this question but would add, if you are an immigrant be aware that a deferred judgment in Iowa is still a conviction for immigration purposes even if it has been expunged