Avocado — Food safety facts
Feed with care · Cats · full breakdown on the linked food page
The flesh is not strongly toxic to dogs or cats, but it is very high in fat and the pit can cause blockage. Never give the pit, skin or leaves.
Short answer
She should be okay, but watch her closely. Avocado flesh isn't strongly toxic to cats, but it's very high in fat and can cause vomiting or diarrhea. Keep the pit, skin, and leaves away from her, and call your vet if she seems lethargic or has an upset stomach.