If the bees have decided to supersede the queen, then saving her is a waste of time. Been there, done that.
The rescued queens turn out to be useless, the bees have already decided she was not good enough, the bees know what they are doing.
Age doesn't mean anything in supersedure, if you mark your queens you will be surprise how many times supersedure occurs.
We have had queens superseded in 3-4 months, a lot of the time they are what I call skinny queens, their abdomen doesn't seem large enough as if her ovaries are not working at full pace.