SL75 with 40 Vitality, Embered, and Speckled Stoneplate Ring, and she can still murder you easily. Be careful as some of her sweeping slashes have massive range and hit long damage frames. Some of her slashes are pure bait, because the follow-ups are instant or too fast to dodge consecutively, so try to pay attention to her patterns.
I did this at a much, much lower SL my very first time, trying with a friend that was ahead of me in the game at launch. In the killing attempt, he died at around 80-85% HP when he got grabbed, and I managed to solo to the end. I used a +7 Heavy Claymore in a 40/20 build so far with no infusion, but I believe I had a +3 Black Knight Greataxe the first time.