In the house

I am maybe 7 years old. I am on our inside porch where all of our shoes are. I find a pair of heels and put them on, excited to go show my mom. I stomp in loudly, and my mom is in the kitchen. She starts freaking out about me wearing shoes in the house. I know she doesn't like shoes in the house but I just wanted to show her. And then she yells "Take those shoes off, they're prostitute shoes." I'm confused and don't know what a prostitute is but I think it's bad. I am surprised at her reaction because it's weird and unexpected. I thought she would laugh or something or take a picture. But she is angry and I don't know what I did wrong.