I found out she is under 18.

The context is: I was invited to a threesome with my SD (we are non exclusive, and use condoms, I regularly test as well) which I was super excited about as I had never had one and I’m bi. He said that he met this girl before and she is super interested. I didn’t get her photos beforehand, but we were able to meet for drinks first.

Well, we met for drinks and I had a few conversations (I was enthusiastic but she seemed shy and a bit like she had other things on her mind). She asked me about my age and I told her I was in my mid 20s, and she said she’s turning 19. Then she asked how the SD and I met, and I told her, and she said she met him nearly 2 years ago… which got me nervous and unsettled. She added me on Snapchat (her snap was her REAL NAME) and as he was taking a shower she asked me again what my age was and I told her again, and I asked her (because it was so weird?) and this time she said she was 17. She said she was doing this because it was harder for her to find work and she didn’t want to work anyway, and told me she nearly got trafficked twice, even traveled around the country.

I made up an excuse and left. I’m not sure what to do. I have such mixed feelings - a lot of disgust (at the men involved) and fear.

The age of consent is 16 in my state, but even then if she did meet him about 2 years ago she would’ve been 15.