what happened

so when I was 10 years old my dad was finally involved in my life.. then he told me he was moving away and he took me and my sister into his trailer for the night.. I fell asleep in the biggest bed in the trailer and him and my younger sister were in the other beds.. I woke up and I was still dark out and my sister was on my left side and he was on my right side.. clearly drunk and he was touching me.. he put his hands on top of my pant and was rubbing over my.. girl parts and then he proceeded to try to put them in my pants and I was saying no stop no but trying to be quiet because i didn’t want to wake up my sister.. I kept pushing his hands away and thinking that he thought I was his fiancée or something.. he kept trying all night and eventually he passed out.. I tried to tell my mother and she told me to stop making things up and I was really upset because she didn’t believe me. it’s 3 years later and I moved in with him and his girlfriend who abused me, eachother and her son.. now i’m living with my grandparents and I still haven’t told anyone.. i’m afraid that if I tell now i’ll get called a liar because it was so long ago and because i’m pressing charges on him for assault, child abuse, and neglect that people may think i’m lying.. should I tell the police when they come to interview me?