Found old kik conversation on Girlfriends (18) phone soliciting sexually explicit photos.

Basically title. I'm an 18/M, we've been together for 3 years in July of this year (2017). I found them on her old phone that she supposedly didn't use anymore while fixing it. It was using a fake name and had one conversation. She said things like she was looking for a dom and asked the guy to pay her for sexually explicit pictures. She said once she got money there would be pictures sent. The convo went on for a few hours and no pictures were sent, from her at least. She claimed she hadn't revived money and wouldn't send anything when the guy said he sent money. I confronted her about it and she said that her friend was over at her house and she did it as a joke, which is why no pictures were sent, and said that if she was trying to hide something she would have deleted the messages. It's been about 2 weeks since we've talked about it and it's eating me from the inside out. She's never seemed like the cheating type which is why I'm questioning. but I've always been worried.

Tl;dr - asked guy for money for nudes on Kik in December, no pictures sent, claims her friend sent the messages messing with a guy.

Any advice would be appreciated. Thanks.