how long do I have to contest a will in the state of New Jersey?

First - the will is still not in probate-probate is the process by which the will is authenticated, and letters testamentary are issued to the executor or personal representative of the estate.  The executor may still be in the process of administering the estate.  If there is an asset that hasn't been transferred or distributions have not been made, then the estate is not finalized, and you can still file a complaint against the estate and/or the executor.