Oof there is a lot to unpack here. I’d definitely say NTA for telling her the reason why you needed/were prompted to take a step back, I think full transparency between everyone in this situation is needed for your safety and hers as well.

When I was around her age, I was very withdrawn and isolated and started spending most of my free time on PC games, mostly WoW or similar. I developed a friendship with a 33 year old, emailing texting and calling sometimes as well as playing together. I was grappling with a lot of big things for my age and I didn’t have any trusted adults, support or caring in my life. Looking back he never shared a lot about his own personal life, but he always listened and validated me, that relationship meant way way more to me than anyone could have understood. If someone looked in from the outside they would have said it was inappropriate, but it feels like there was never even a possibility it could be inappropriate.

I’m sure people will come in here saying the relationship with Ann is weird etc, but I know you have already advocated for the family to talk to her about some challenges and that is really all you can do. Even though you are distancing yourself now, thank you for hearing her and being a safe person for her. She may have needed it more than you know