He can kick you out.
mdalyandddaly,
Your friends are wrong. You have no rights under New Jersey law to live in your step-father's house unless:
1.) You are under 18 (a minor).
2.) Your name is on the title of the home.
3.) You have a signed lease agreement in effect, and you pay rent.
If none of these conditions apply, by the law he can kick you out at a moment's notice. I hope this information was helpful to you.