K.G.
My 18 yr old daughter is acting up too...she wants to be independent and make her OWN rules but she forgets that she is living in MY house. I almost asked her to leave about 1 week ago. I only stopped because she calmed down "a little bit" and I know that she will be moving out soon...as she now has a job and she is saving up money to move. I can only tell you what I think.
If she has a job then charge her room and board. If she doesn't have a job tell her she's got 2 weeks to get a job and that you will be charging her room and board. Reqiure that she save a certain portion of her check so that she can afford to find HER own place. You can save up the money she gives you and present it as a housewarming present when she saves up enough money to move if you choose. Make out a written contract stating the RULES OF THE HOUSE that she must sign if she wants to remain living with you. Put it in black and white what is expected of her and that any infractions of the stated rules is grounds for eviction. You can put in the contract that she has a 3 strike rule so if she is late and she doesn't have an exceptable excuse or she didn't notify you that she would be late and get an aggreement from you that it was acceptable she has 3 strikes then she is out.
You raised her...you did a good job...but your job with her is done and now it's time for her to sink or swim. You have a responsiblity to the younger children in the house. By accepting her behavior you are teaching the younger children what is acceptable behavior and what is not. You will always love your children and I am not saying that you don't help her when she needs help but by letting her walk all over you and treating you with disrespect you are teaching her that it is ok to be disrespectful to other adults and to your parents. You are not "helping" her when you teach her that there are no Consequences to her actions. Could you treat a boss in the workplace like she is treating you? What would happen if she showed up an hour late for work and basicly told the boss get over it?
You will do what you think is best and you will get the credit/blame for whatever the outcome but this is really up to your daughter...can she live by your rules of your house...or can she not? The choice is really hers and it's up to you to enforce the consquences of her decision if she chooses to stay. That's part of being an adult. Would your Mother have let you stay in her home if you treated her in this fashion? Your not being mean by demanding the respect you've earned over the years...she's being selfish when she behaves as if she is the only one in the world who matters.
Good luck...I know I need it too...lololol