I just want to say I am 5'7". I weigh 127 lbs on a very tiny frame and I am slender, I wear a size 6. At 127, my wrists and collar bones are already pronounced and it hurts the bones in my butt to sit on a hard wood floor. I could not imagine weighing 90 lbs, I would be a walking skeleton.
Gosh I hope we did not scare you off. come back .....
what we give as advice is just that, we do not judge. We are giving your our life experiences as we see it from a few years down the road from where you are now.