he was 21 and he knew how old I was...

Just prefacing this with the fact that I have never discussed this story in detail at all with anyone since it happened 5 years ago. Maybe two people other than myself know small details but not to the extent I am sharing here. I am using this opportunity to hopefully help myself let go of some of my guild, though I'm not sure my story will be helpful to anyone else. Also prefacing that my story involves details of sexual assault so content warning for that. When I was 15 I was in the midst of some extreme emotional depression and anxiety and part of that experience was immense loneliness and worthlessness. I was only just beginning to grasp what my sexuality may be and was only just beginning to have sexual experiences, in particular with other men. I attempted to appease my loneliness by talking to guys online. Eventually I worked up the nerve to meet up with someone, he was 21 and he knew how old I was. He drove to my house and picked me up in his car and we drove a few blocks away and started hooking up in his car. It was the first time I had ever had sex of any kind, let alone anal sex. I had no idea what I was doing or how to communicate anything. He asked me if I wanted him to fuck me and I said yes because I truly thought it was what I wanted at the time. He didn't use any lube, condoms, or communication. He was slow but I was too anxious to communicate that it hurt, I also feared the rejection that might happen if I expressed any displeasure. I just kept quiet and waiting for him to finish, which wasn't long. I asked him to drive me home and as soon as I walked in the front door I broke down crying. I have struggled with this experience ever since. I wasn't intimate with anyone else for two years in part due to the anxiety. I blame myself, I consented, I wanted it when it was happening even though I didn't understand the decision I was making.