"Three times Lorien had been assailed from Dol Guldur, but besides the valour of the elven people of that land, the power that dwelt there was too great for any to overcome, unless Sauron had come there himself"
She is not a warrior, and many would be stronger physically but she is extremely powerful. In the first age she was deep in the counsels of Melian. She was probably the most prepared person in middle earth for a direct confrontation with Sauron himself.
She might have even been the equal to Feanor the most powerful elf of all time. Fearnor started in a blaze of glory which quickly diminished, while Galadriel slowly increased in strength and presence through the ages.