That I don't know, but I looked up my correct weight/height on-line (140 at 5'7"), and I hover within 2-4 pounds of that. Depends on your age, too. Depends on your bone structure (measure your wrist at the thinnest part) and look that up on-line. Also depends on how fit you are (muscle weighs more than fat -- which makes a lot of BMI's wrong... Body Mass Index). Fitness may depend more on how you feel and the results of blood tests including thyroid, heart exam, lung exam).
A quick search for BMI (body mass index) showed 150 as a 'healthy' weight for your height and age. Depending on your heritage, you may be prone to be more heavy than you will see on a generic scale, there is nothing wrong with that. If you feel healthy, you are at a fine weight. Regardless of what some generic scale says.
If you want to loose weight for yourself, set a goal you are happy with that you can actually attain. You don't have to be at any particular weight as long as you are happy with yourself.
I have never fit this, when I was younger it was funny to watch the nurse get on the scale after I got off, even when I was 225 on a 5'11' body.
Well up to you. since it is your body, and you are the boss of it
120 is acceptable. 130 would be the limit. Anything above is overweight.