My girlfriend made an inappropriate joke

I (31F) am in a 4 year relationship with my gf (29F). For some reason I always found male anatomy repulsive. It's indifferent to her. Nothing wrong with that. She knows I find it repulsive. Not only that I even don't like strapons or penis shaped dildos. Today she told me she wanted to try a strapon on me. I said I don't like it. Then she said she wanted to have sex with me imagining she is a man. I said I hate that idea. Then she said (jokingly) if you don't shut up I will wear one and rape you. This is not a joke for me. I have anxiety and I have also been SAd before. I cried and she said its a joke. Is it normal to joke about these things?