What options if wife changes mind after consenting for mutual divorce?

Assuming you both are Hindus, Mutual Divorce is recognized under Section 13B of the Hindu Marriage Act.

Section 13B states that the parties can jointly move a petition for dissolution of marriage by a decree of divorce in the District Court on the ground that they have been living separately for a period of one year or more, that they have not been able to live together and that they havemutually agreed that the marriage should be dissolved. The Court shall then record the joint statement of the Parties and pass a First Motion Order giving time of 6 month to the parties to resolve their dispute, however in case the parties are unable to resolve the issues within the stipulated time, the Court shall pass a decree of Divorce. So therefore divorce by mutual consent takes about 6-7 months.

You should file the petition for dissolution of marriage by mutual consent as soon as possible and get the First Motion order passed by the Court.

Thereafter, even if your wife wants to withdraw her consent she will not be able to do so as recently the Courts have held that One party cannot withdraw consent to a divorce by mutual consent once the First Motion Order has been passed and MOU has been acted upon.

Regarding mediation, this can be used to settle any pending dispute like with respect to the maintenance or other pending complaints filed by your wife against you. Mediation cannot be used for getting divorce. It is merely to come to a settlement regarding disputes.