Teenage problem...pls help?

hello all....i m a gil who is 15 yrs old. i m 5 feet 3 inches or probably 4 inces...i m 65 kg n luk quite fat...i really want to lose fat as i am fed up of my dresses gettin tight each day....it does not bother me to lose weight bt i want to lose weight in inches....my mother does nt allow me to do the cabbage soup diet plan...she says ..dat it may have side effects on my face n my glow(i have a glowy n fair skin)....so pls suggest sme exercises n sme diet plans to go about ..i want to lose around 10 kgs in 3 months...i might join sme gym too...is dat fyn??