You keep reading that you have to be 18 because the law considers you to be a minor until you reach age 18. A police officer's reluctance to enforce the law has no bearing on what the law is. (While some officers choose to ignore the law when it comes to a seventeen year old, it would be just your luck that your parents call an officer that actually enforces it.) To make your own decisions about living arrangements, you must be emancipated by age (18), occupation (military), marital status (married) or court order. At age 17, waiting for your next mother makes more sense (in most cases) than pursuing the court order.
I hope this information helps answer your question(s).
~ Kem Eyo
The above answer is a general explanation of legal rights and procedures. It does not constitute legal advice. Nor does it establish an attorney-client relationship between the individual posting the question and the attorney providing the answer.