Is it possible to get a really slender body?

I'm about 266lbs, almost 5'7. 15 years old. I don't have a big belly its kinda flat, i do have big thighs and . im 36D in bra size. most of my fat is in my arms and legs and thighs, i do need to lose weight on my stomach. im very curvy. im actually small boned, my fingers over-lapp and i tested on skinny small boned people to make sure using my fingers about same size. so if i drop to like 115, will i be skinny like size 4 or 5? and with a washboard stomach?