If she said you are a disappointment to her, then you should accept that she is telling the truth about how she feels about you.

This does not mean you are a Disappointment to yourself or to anyone else. It is not a global pronouncement about you to everyone else in your life.

Look. If you made an incorrect statement like, "I know you do not like fish," then you made a mistake. It's annoying and arrogant for you to say you know her likes and dislikes when you've never met her in real life and haven't known her for long.

It should not be a big deal if you say you are sorry.

If she keeps dragging it up, over and over, then that's very irritating and unnecessary.