divorce decree change

What is the name of your state? Indiana

I've been divorced for 3 years. We had the same lawyer and agreed on everything in the divorce, I filed. After three years, can my ex get an attorney and go into the decree and change things that have already been decided by the decree like pension and college payments?? The attorney we had told me that after 30 days the settlement was set in stone, is this true??

Once you've both signed it, it can't be changed without going before a judge. They can't ust change something and hold you to it without a judgement.