Sexual abuse

I was continuously raped my my brother when I was 12- 14. It is really started to have an effect on my mental health. Being diagnosed with PTSD. I didn't report it to the police. But I'm thinking of doing so. I am in my 20s now. Has anyone been to the police about a rape issue? What happened, what evidence do they need ect. I'm really scared about going to them because I have heard a lot of cases are not taken seriously. Would love some advise. Thank you x