What is considered thin for my height?!

What is considered thin for my height?

I'm around 5'9 and a female.

2 days ago
i am also 15

I am, also 5'9 and female

My lowest weight was 143 and my neck bones were sticking out. I didnt have any curves.

I purposely gained up to 150-155 and I look great at that height. I am a size 8 (9 Juniors)

I think that anything below 145 would look too thin. 145 -155 is a nice weight.

You will have a nice booty!!! :)