I was left property 5 years ago when I was minor and am now 20 years old.  I don’t want the property and want to disclaim it.  Can I still disclaim it?

You cannot disclaim  when you were a minor yourself. You can generally disclaim you interest in the property after your twenty-first birthday. No act or conduct prior to your twenty-first birthday, other than a written acceptance, shall constitute an acceptance of any portion of the interest. So you can disclaim your interest in the property now.