how to lose thigh fats?

im 13 weighing 42kg and 151cm.i have a rather fat thigh.i hate it when my legs get tired and i have no choice but to just lay my thighs on the seat which make my thighs fat.i don't want muscled thighs but i would love to have a thigh gap!any idea how to reduce the fat?and also having a thigh gap?