Is all of this activity while in the cage? if so it is likely territorial aggression. If the attacks stop on neutral ground (some place in your house she cannot see from her cage) then you'll know for sure its territorial.. Iguanas are known to quite territorial.. Don't let your guard down in any event.
Ill iguanas are also known to act aggressive so you may want to look into a vet visit. If they show signs of illness in the wild then predators are more likely to go after them.. So its a basic instinct to them to act like little assholes when they get ill. If she's that old I would definitely take her to a vet in any case for an exam to see how she's doing.