I got myself into a big mess...?

Ok... you say you are close with her parents? Maybe you could talk to them, just them, without their daughter around, and bring up this issue. Without disrespecting them in anyway. Just talk with them about it, and say that it is really hurtful when she says the things that she says to you. And then ask them about their opinion. And then if you get the chance, ask Adeline if you could speak with her about something. When you two get together, just state the issue at hand, with a calm tone... even if she gets fired up. Honestly, if you keep your cool throughout this conversation, it'll piss her off more (most likely) and you'll feel good because you are being "the better person". Im not really aware of the other factors that play into this situations, you really just have to judge the situation and whatnot. I really hope this helps? Maybe?