selling a dress and received this response. am i being sensitive by wanting to block this buyer?

hi! i’m selling a lot of my clothes that are too big for me due to massive weight loss and this person has liked a few items and asked me to hold this one in particular. i agreed and then she backed out saying her boyfriend thinks the dress looks matronly. i don’t really care if she changed her mind since she didn’t buy it yet, but i just think what she said was rude. am i crazy for wanting to block her so i don’t have to interact with her in case she tries to buy something else from me? i know i’m probably being petty but who says that?? it would have been mostly fine if she just said she didn’t want to buy it anymore. what am i supposed to do—say yeah its matronly that’s why i bought it to wear to my friend’s wedding lol?