The above answer has nothing to do with whether or not you can change back. If the whole issue is based on a date, you need to determine how important that date is to the final decision. If you are fighting over one piece of property, you have to decide if that is important enough to put the whole agreement in jeopardy. Yes, you have to live with the final judgment, so make very sure.
Also, you already signed off on the property agreement. You would have to show there i a very good reason why you changed your mind. The date dispute should have been discovered before you signed. You will have to explain to the court why it was not discovered.
A lawyer licensed in Maryland would need to discuss this with you.
You always have a right to file an amended complaint for divorce. Just as a contested case can become uncontested; an uncontested case can become contested. Many times the parties thought the issues were resolved and someone changes their mind as to a material issue. This results in a change in the status of the pleading.