NTA. I think you handled it appropriately. This woman was bigger than you, was being aggressive toward you, and had already followed you to continue the verbal assault after you attempted to walk away. You didn't know that woman or what she was capable of.

You were left with the options of fight or flight, and flight had already proven to be ineffective. Short of resulting to physical aggression yourself, the safest thing for you to do in such a situation is make the other person think that physically engaging you would be a bad idea. Best way to do that is to respond more aggressively than the other person because they'll almost never be prepared for that.