If no one has told her that what she said was offensive, and she really didn't see/mean it to be offensive, then she has no way to know that she was offensive.

You perceived her to be offensive. She perceived you to be offensive. You didn't think you were offensive, so why would she? However, she chose to tell you her opinion on your offensiveness. You chose to not tell her.

That isn't anyone holding you to a higher standard. If no one else told her that she had been offensive, and no one else told you when you were being offensive, then you have no idea if anyone else thought that either of you were being that way- they either thought neither of you were being offensive or chose to keep their opinions to themselves.

But nothing you've shared implies that you are being held to a higher standard.

ETA: and if she had meant to be offensive, well, most people who are intentionally offensive are often some of the quickest to be up in arms if someone else offends them. Just take a look in most of the current media and politics for examples of that!