My mum thinks i was raped?

She thinks I was raped when I was like 5 by a neighbour, but I don't think so because I have really good memory and I would of remembered it. She is obsessed with it though and everytime she sees me she brings it up.

Even if I was raped I don't understand why she constantly brings it up, there is no way of even punishing the person if I was because it was so long ago and there is no evidence at all. I told her before to stop talking about it but the moment I saw her again she started talking about it. Why is she so obsessed? It makes me uncomfortable and grosses me out.

She also "claims" she saw my neighbour raping me but when I asked why she didn't call the police (like any normal parent would) she got all weird about it and tried to make up different excuses everytime I corrected her, she then got fed up and changed the subject because she couldn't think of anymore excuses.

I think she is making it up but I don't know why and why she tries to bring it up so often? (Keep in mind she has lied about things in the past, this is why I'm so doubtful)