I'm in the "kick you out at 18" group, and my fiance is "kick you out at 18 IF you are not in college / are not getting good GPA in college"
A good parent works him/herself out of a job. By the time a kid is 18 s/he shoud be able to be independent.
I signed a lease on an apartment on my 18th birthday, went on vacation with my family, and moved the day we got back. I bought a house before my 19th birthday!
My parents taught me along the way - how to write checks, balance a checkbook, make a budget. Opened a checking account for me at 16 when I got my first job. I had to pay my own gas and car insurance when I drove my parents' car, bought my first car without a loan or help from my parents.
Was I good with money? heck no! My parents gave me enough rope to hang myself with. The consequences were clear. No money = no gas, no insurance, no driving, no buying a car. No driving, no buying a car = no job, no money.
My kid is 3. He already knows he is out at 18. MY JOB is to make him ready! That is cooking, cleaning, budgeting, knowing about credit scores, insurance policies, driving, FAFSA, study skills, interview skills, work ethic, etc. A big job!
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Teens don't listen well. Write her a letter and put it under her pillow. Don't write anything that could be taken badly or used against you, of course. Maybe make a point to write her a letter once a month. Tell her about the good things she does and the good qualities she has. Tell her why you care about her behavior. Tell her what your expectations are. Explain the consequences.
Take the argument out of it. Write it down so she can read it, digest it, reread it...