Juvenile Justice

Dear sir i was arrested in 2009 on charges of cheating (420).case was registered against me by Bihar state education council.i was 15 year old that time .I was in prison for 7 days.After that petitioner didnt pursued that case further .Now i am 24 year old and cleared State police exam .While filling form they had asked me if i had ever been arrested or any criminal case pending against me if yes then please provide further detail .since i was minor that time i had no data about that case neither with my parent so i marked no .Sir i am not sure what to do now .