I had a male mojave that was acting similar this year, and also thought it might be because he was in "breeding mode". It actually turned out he wasn't happy with the way his enclosure was arranged and it took the addition of some more hides, sphagnum moss and different substrate for him to settle down and eat. He had been in the tank for a good 8 months and never had a problem eating, but for whatever reason he didn't feel secure suddenly.

Could it be that there is something else going on with her? Maybe look over everything in her enclosure to make sure that she feels warm, hydrated and secure, because it seems that if they are evenly slightly unhappy, they don't eat. Also, when was the last time she went in to shed?