Advice for turning myself in/should I even do that? (TW: suicide, self harm, sexual assault)

First off, I’m based in Ireland. My basic situation is that I sexually assaulted my sister a year ago. I haven’t done anything like it since and have kind of been isolating myself. She’s been saying suicidal stuff and struggling in school, also some issues with my parents involved. I think she cuts herself. I have been seriously considering turning myself in, but I can’t afford a lawyer/a solicitor by any means. I’m 19, unemployed and rely on my parents for everything, I have a place in university starting in September. I might be on the autism spectrum and was in the process of getting a diagnosis, was meant to follow-up with a psychiatric one but I kind of left it at that because it’s too expensive. My parents don’t know and I feel awful. I think they do suspect something is off. They might know if they’ve read my journal, but I’m scared that they themselves wouldn’t do anything about it or that things would change for the worse basically, but maybe that’s inevitable at this point. I guess I could just tell them directly.

We’re going on ea family trip to visit relatives outside the country and I feel that I should maybe take action before that, although that would probably be an absolute shitshow if I did. I feel the need to take action as soon as possible though, because things are getting really ugly at home. I promised my sister I wouldn’t call social services and go to therapy instead, which I’m doing now, but I’ve been dancing around the issue and kind of just addressed other stuff. My sister said she would go to therapy if I went and I’ve started therapy but she isn’t going, she’s in a busy year in school and I guess she doesn’t want people to think anything’s wrong maybe. I feel bad making my Dad pay for therapy even though I feel like it’s helping because I have been dodging the actual problem.

I guess I’m willing to face the consequences but have no idea what will happen, someone suggested I went to the public defenders office in a previous post I made, but again I can’t pay a solicitor. I don’t know if I should tell my parents or what. My mother is really harsh to my sister sometimes too and I wonder if she’ll be softer on her if she knows what’s going on. But I kind of want to make sure my sister gets help. At this point I just want an idea of what to expect kind of or how I should approach the situation to turn myself in, or if there’s anyone else I could speak to…I was going to tell my therapist but I almost think it’s a waste of time to do it through her if she’s going to report it anyway. And I know she would be obligated to call social services but maybe that’s what’s best?