Why am I scared to talk to her?

My uncle sexually abused me for years, and it's finally came out, but my mom wants me to talk to her, and tell her what happened, like into detail, i don't know why I'm scared to talk to her about it, but i am, and she's getting really angry, because I wont talk to her, and i don't know why I won't, if I don't tell her there is a high chance I'm going to be put into care, can anyone help me