I've been where your daughter is, at the same age. You're doing an awesome job just by KNOWING what she's up to. My mum didn't realise I was slipping into an ED or that I was smoking. It took me until I was 20 to realise the damage I was doing and help myself. Part of the reason I'm slightly chunky now is that I don't want to fall into the trap again. I can't describe how addictive it was to deny myself EVERYTHING. And I still can't explain why.

Keep in her face about it. Do not back down. She needs your loving hand to guide her. You're a wonderful, present and observant parent. Sending you all some strength.