I’m sorry - I’m not sure how your post got flagged for pre-approval.
Technically, either side has the ability to either “set aside” (throw out/redo) the Judgment or to “modify” the terms of the Judgment. There are time limitations on trying to set aside the Judgment that are based on the specific legal grounds upon which your ex spouse is trying to set it aside, but it’s typically six months. As for modification, she has to demonstrate a change of circumstances. Depending on what she’s trying to modify, it may be easy or difficult to demonstrate that change. For example, modifying child support or custody is fairly easy, even after the judgment is finalized. Trying to modify spousal support is typically much more difficult.
Overall, the chances of modifying or setting aside the judgment comes down to the actual agreement itself. For example, if the judgment says something is final and non-modifiable, doing so in the future tends to be extremely difficult. If, however, the Court “reserves jurisdiction” to change something, then it’s a lot easier to do so.