In order to end your child support obligation, your child must be declared emancipated. This is not automatically done. If you and the other parent both agree that the child is emancipated, then you both can execute a consent order for a judge to sign that declares the child emancipated. If you are not in agreement, you must file a motion where the court will determine if the child is emancipated.
In New Jersey, emancipation does not automatically end when the child turns the age of majority, which is 18. Emancipation occurs when the court determines that the child is beyond the sphere of influence and responsibility by the parent and obtains an independent status of their own. Each case is fact sensitive.
Generally, if a child is still a full-time student, a court will not emancipate them. Emancipation does occur if the child joins the military, gets married, or ceases to attend school on a full-time basis and obtains full-time employment. It is therefore important for you to speak with an attorney to determine whether or not a court would consider your child to be emancipated.