Heyyy! Don't you worry dear. She may have her own reasons, and I am sure they are not related to you. Later she can change her mind and I advise you to be ready to go. You may check out
https://therighthairstyles.com/wedding-hairstyles-for-long-hair/ for a wedding hair-do, so that once this happens you just pick up a present and go, without thinking too much of your look.