Obesity crisis-what to do?

Hey I am a 16 yr old girl, and I am 5 feet 4 inches tall and i weight 76 kilos. i hav a very busy schedule as a 10th cl student so i dont get time to do much of physical activities. then also i try to take out somme time to xercise on my twister. i eat very less, and i dont hav ny cravings for sweet or salt. my mom is fat too. i dont hav thyroid also.. is there any way i can atleast reduce 10 kgs to bring my BMI in a proper position.?