I told my family that I was molested by my cousin over 10 months ago. I realised just now that they don't believe me. I can't move out, I can't ignore them. What do I do?

I don't mean to say she molested me 10 months ago, I mean I told them 10 months ago.

I didn't get any sympathy. I didn't get a hug. All I got was "she was too young to know what she was doing". She wasn't though. She was 13-14 years old. When I was 13 I knew not to lock myself in a bathroom with a child, strip them naked, start touching them and making them touch me. I knew not to make them finger me. I knew not to have them strip me and then lick me.

I'm 21 now. I suffer borderline personality disorder. I'm struggling in the same way I was struggling almost a year ago. I might have to go back on Quetiapine because I can't do this alone. People try to convince people like me that we're not alone. Fine, some might have support but I don't. I have literally no one. My friends found out a few months ago but they've been next to useless. My family are still talking to my cousin like she did nothing to me, like she didn't royally fuck up everything for me. My fiance is in fucking prison in a third/second world country where he has to pay the guards to let him text/call me once every few weeks, and when he calls me all he's interested in talking about is doing gangbangs and me drinking his piss and whatever when he comes out. I don't have one fucking person to help me through this.

Why did god have to make me come into this world. I can't handle it. I don't owe my family shit, yet I can't commit suicide because for some dumb shit reason I feel guilty. It'll be at least 2 or 3 months before I can see a therapist. I wish I could just jump in front of a train and die because I can't handle seeing my family every single day knowing they don't believe me. No one was in the bathroom with me when she was making me do everything to her. I was between 8 and 10 years old. She convinced me that it' was a "private game". How was I to know better? She knew what she as doing. We would only play this game when my siblings were asleep or when there were guests in the house and there were so many people that no one would think twice if we went missing for 15 or 20 minutes. The older I got, the more aware I became. When I started learning about sex and acknowledging that this game we played was actually really inappropriate I told her I wanted it to stop. I think it did quickly, but that may have been because my family moved away so we rarely so my cousin and her family. I was just reaching 10 at the time.

Bonus question: Is 13/14 an age where teenagers can get away with molesting children? My family certainly think so but I genuinely don't know. UPDATE: I just read up on child on child sex abuse. Apparently it's considered sex abuse if the molester is educated/aware of sex and sex acts. That's usually around puberty or when they receive sex education. In England we get sex ed at 11 years old. Might be earlier now. I don't know.