It's hard to know, since she's a first time broody.
I have hens that will sit forever. Seriously. They hatched muscovy eggs, and were sitting a week before I gave them the eggs. So that adds up to six weeks of sitting. It's a long time for a hen to sit. It does take a toll on their health.
I always try to make sure that my hens don't lose too much weight when they're broody. Every day I give them a bowl of chicken feed mixed with water. For some reason, mine go crazy for it when it's wet. I take them off the nest, get them moving around to break the trance, and feed the treat. I make sure that they are able to eat as much as they want without any of the other hens bothering them. I think that helps some, but they still lose weight. It's inevitable.
So, I guess my point is that it's possible she will continue to sit long enough to hatch another set of eggs. As for whether or not it's a good idea, well, you'll have to be the judge of that.