Can I Prosecute This Guy? Will My Witness Hold Up?

Location: North West Arkansas
In February 2025, I was 18, my boyfriend at the time was 20, and another man was 23. We were participating in a threesome, but I had explicitly told the other man no to anal sex repeatedly throughout the night because he kept asking.
Despite me repeatedly saying no, he penetrated my anus with his penis while I was facing my boyfriend. He was behind me and held my hips while he did it. It hurt, and I froze. I didn’t say or do anything afterward because I was frozen, but my boyfriend asked me if he had put it in my ass, and I said yes. My boyfriend didn’t actually see the penetration happen, but he witnessed that exchange.
The day after, I had conversations with my boyfriend over text about how I didn’t want anal sex. I still have screenshots of those conversations. I also have screenshots of the other man admitting to stealing a bottle of Adderall from us. He was also giving us alcohol when we were underage.
My ex-boyfriend is willing to testify as a witness if I decide to report this. I haven’t contacted the police yet because I’m scared I won’t have enough evidence for them to take it seriously, or that they’ll dismiss me because my boyfriend didn’t actually see the penetration happen.
I contacted an attorney today to see if I can speak with her about my options. I’m trying to figure out whether this could be prosecuted as rape or sexual assault under Arkansas law, whether the screenshots and my boyfriend’s testimony could help, and whether it’s worth pursuing a criminal report this long after the incident.
I’m especially worried about not being believed or going through the stress of reporting it only for nothing to happen. I know participating in a threesome doesn’t mean I consented to every sexual act, and I had explicitly refused anal sex beforehand, but I’m still scared that I won’t have enough evidence.
Has anyone dealt with something similar in Arkansas, or does anyone have experience with how these cases are handled? I’d really appreciate honest advice about what to expect, how to report it, and what I should do to protect my evidence.