If I am 18-years-old and still in high school, am I able to move out of my parents house?

You should review the laws on the rights of minors and what is the age of majority in your state. Although 18 is generally considered to be the age of majority, there may be some other factors besides chronological age, that need to be considered. You should consult with a family law attorney to get the specific rules for where you live. You may also want to consider doing some counseling so that you are able to plan for a successful move out (as opposed to a boomerang) experience, i.e. getting a good handle on what it will cost you to live on your own and having a good income source for yourself as once you have moved out, you will not be able to rely on your parents for support.