If you are 18, you can do whatever you want. However, don't be surprised if everything you think of as "yours" suddenly becomes "your parents'". Think about your bed, you sheets, your dresser, your clothes, etc. Think about, most likely, your car and the insurance on the car. Your health insurance.
You will have to pay for rent, bills, and groceries, which means you will have to get a full time job which means dropping out of high school. Not having at least your high school diploma means you can't get a decent paying job.
So, yeah. Go ahead and move out of your parents, sleep on the floor some where as you manager McDonald's.
What aspirations you have!