If you choose to go under the Visa Waiver Program, you take a risk, because you do have a criminal record. It's very unlikely that this will be picked up at immigration, but there's always a chance. My son is in exactly this position & chooses not to risk it. Personally, I wouldn't be able to stand the stress during the flight, wondering whether I was going to get in, or was going to be put on the next flight back.
It was exactly because of this thought that when, many years ago, I was ticketed for exceeding the speed limit in Kansas, that I chose to pay the fine.