At 18 many kids feel they no longer need to obey their parents since they are now adults. I would recommend that you sit down with your daughter and let her know that you feel she is not obeying, and that since you are supporting her financially and she is living in your home, she needs to obey some basic rules that you set forth. Some suggestions:
- If she is not going to college she doesn't need to be financially supported, she can and should get a job. Make up a list of the costs associated with her living in your home including a charge for rent, utilities, etc, plus let her know she will need to pay for her own clothing, toiletries, etc. You could give her the option that you will pay all or a certain % if she is going to college and making adequate progress towards a degree (be sure you let her know what you consider adequate).
- If she is going to live in your home, regardless of whether or not she is paying for her room and board she needs to follow your rules. Let her know what the rules are (such as letting you know where she will be in case there is an emergency or something happens to her), and that if she is not goign to follow the rules that she will need to find her own place to live. Make it clear that you are not abandoning her as a parent, just that if she is going to act as an adult without rules that you expect her to take on the responsibilities also, and until she is willing and able to do so she needs to follow the rules of your home.
- Explain that it is important that you know where she is, it is both a safety and a courtesy issue. Most roommates even have the courtesy to let one another know where they'll be and when they expect to be back in case there is an emergency or someone needs to reach them.
You might have to get tough with her, but if she is deciding she wants to make adult decisions, she needs to take on adult responsibilities. If you want to help her with college either by providing her with a free home and what not and/or paying for tuition in full or part, then make it clear that those things are only available if she is actually attending school to make a better life for herself long term.