At the time of marriage the gril was minor, not both the parties. Following sec of the Hindu marriage act may applicable on your case. Sec,13 (2) A wife may also present a petition for the dissolution of her marriage by a decree of divorce on the ground,-
(iv) that her marriage (whether consummated or not) was Solemnized before she attained the age of fifteen years and she has repudiated the marriage after attaining that age but before attaining the age of eighteen years.
for more perfect answer, more details regading date of birth of the girl date of marriage and the cause for delay in filing the petition in regard to the marriage is required.