Homework issue first: IMO the problem with asynchronous development in executive function is that many of the "natural consequences" approaches have a disproportionate impact. DC won't complete SAT registration? If one lets them suffer the "natural consequences" DC may miss all the financial aid and application deadlines and not be able to go to college. Even if one explains this to DC, DC may just not be fully able to realize the true impact of their actions. Additionally, DC may be getting bad advice from others or observing students with different life goals and not believe that the dire consequences you describe will actually occur. Ugh. It has been my experience that this actually got worse with age as the stakes got higher and the resistance to parental advice became greater. What worked for us? We found that having DC develop a plan for which college (substitute high school in OP's case) and look up herself what the requirements for entrance to each school were made clear what classes, grades, and tests DC needed. This helped a lot to keep DC at least on the main road to DC's goal. Other parent's we know used a tutor and if their DC did not want to have a tutor made it grade dependent; i.e. if you don't want to spend 2 hours a week with a biology tutor your grade must be X and your assignments must have less than Y number missing. Some parents use a homework coach (see an article on these here: http://www.nytimes.com/2010/11/08/nyregion/08homework.html?_r=0 )

Finding a way to both enforce parental rules and de-escalate situations is tough. Really tough.

Lying second: I'd urge you to make really, really sure that there is not anything "weird" going on with your DD. I found long car rides out of the city best for these kinds of conversations. Preferably with DC's phone (sadly) accidentally put in the trunk, "can't stop on the freeway". By "weird", I mean the big bads: bullying, drugs, sexual abuse, and the like. Time to check the phone, facebook, email, and other accounts. If nothing "weird" is going on, then reading some of the books that others have suggested on this site may help (discussed here: http://giftedissues.davidsongifted....4858/Dealing_with_manipulative_beha.html )