Big, what you are saying feels kinda bonkers. The one thing of real merit is that they would have a tough time hitting her - thats totally fair.
I am fairly certain that Rodan could basically ignore "rain fire" in much the same way CM did based on how volleys of modern missiles did squat to him, and more significantly, he literally woke up in an erupting volcano that was sending out shockwaves capable of disturbing fishing boats kilometers away. Not a scratch from either thing. Ghidorah can one shot KO him with a single burst from a single head. He has three heads. If she gets caught by those 3 bursts, she is dead.
Even if she could inflict damage on Ghidorah (doubtful) he could heal faster then the work she is doing. I say her inflicting damage is doubtful because the dude can ram full speed into the 30k+ ton Rodan, who himself is flying full speed, and take a total of zero damage from it. The force involved in such a collision would be insane. He got shoved but not harmed from Godzilla's atomic breath. Godzilla smashing into him at a full run created city spanning shockwaves and he was fine. He can heal an entire head and neck in minutes. A small wound to an eye, assuming it hurts at all, would be super easy, barely be an inconvenience to heal.
This isn't even factoring in all the other Titans. I think Ghidorah alone is outside of her scope to kill. Best she can hope for is avoiding each other indefinitely.