My 18 year old is failing her senior year and has been baker acted twice this year. How do I legally kick her out?

Do you have any idea why there is this sudden dramatic change in her behavior? It is possible that she has suffered some sort of significant trauma that you are unaware of. I understand that she is technically an adult, but children don't suddenly wake up on their eighteenth birthday and know how to function. If she is suffering from a drug problem you may be able to get her into treatment through a Marchman Act. If she has developed a late onset mental illness you may or may not be able to get her some help. You could try conditioning her remaining in your home on her getting some counseling and treatment, and participating in family counseling. If you want to get her out and she has not been paying rent you will have to file an ejectment action, and you should contact an attorney about that.

I agree with both Attorneys Morcroft and Smitten, but if I were using legal process I would try an unlawful detainer action before I would use ejectment. That being said, before I would use legal process to get my daughter out of the house I would find an apartment for her, preferably with her involved in the process, put down first, last and security, help her move and then change my locks. Alternatively, would be interested at all in a job in the military, say the Coast Guard, would they want her? Good luck.