I've not studied law but what I do know is that in my country, The Netherlands.
A person can move out before their 18th birthday but their parents will still be considered their legal guardian until their 18 therefore still responsible for you and your actions. If you wan't to move out before your 18th birthday and your parent will not allow it for some reason, they can limit you and keep you from leaving.
But mostly you can only move to a student housing program because any other kind of accommodation requires a steady job or other financial reassurance which of course could also be your parent income for example.
But if you have serious problems with your parents you can get social services involved so that your parents can be relieved from their guardianship and then the state become's your guardian. If that's the case you will be placed in foster homes or group homes especially for children under 18. When you reach your 18th birthday you will receive a training of sort to learn how to take care of yourself and live on your own. (personally I've know teens who have been in this situations and their experience with foster homes weren't great because they kept being relocated to another location away to a new school and far from friends and sometimes had biased foster parents ect.)