It could go several ways. Either you both heal together , she’s claims it never happened and no idea what your talking about or you stir up feelings she’s been trying to work past. I know for me personally I’d just seek therapy .

Maybe start with a therapist and see what their opinion is.

I had a similar experience except with a cousin. Her brother sexually assaulted her fairly often and he did it to me too when I stayed the night at their house. I also didn’t realize what had happened until I was much older and to be honest I didn’t really remember it until then either. I’ve decided I wasn’t going to say anything because after finally talking about it to A close friend of mine and my boyfriend, I realized at this point it would be my word against his and I thought it would be better and easier on me if I just found ways to move forward from it instead of going back and reliving the experience. His sister also took it a lot harder than me she had severe mental health issues afterward from the trauma and I didn’t really wanna put her through that again as well.