Don't try to push her to do everything at once, i.e. change her diet, regulate exercise, change sleep habits, write in her planner, be responsible for personal hygiene, etc. Just pick one small thing to work on at a time. It's hard enough to make one life change, and trying to force a lot of changes on her will only increase her anxiety. She may be feeling like she can't ever do anything right, so why bother trying. I know I get that way sometimes. I know it's frustrating for you, but remember it's frustrating and hard for her too. She is approaching adulthood, but she's not there yet. There is time for her to change her habits. And no one says that all bad habits must be solved by age 18 anyhow. ADHD is something that takes a lifetime to learn to manage.