This has gotten pretty confusing.
If you're only 17, 5ft 4in and weigh 125 lbs, my guess is that your pants are more like 32-34 inches at the waist. that is NOT your hips.
However, if you're accurately measuring your hips, they could easily be 36 in.
If you measure your waist, you measure about a half-inch to an inch below your belly button. However, your hip measurement is across the broadest part of your lower body, which is about 3 inches lower and goes across your hips and butt.
So perhaps you'll need to look at the waistband of your jeans for the size lable on your pants. I'll bet they are 32 or 34 inch on the size lable.
Either way, if you weigh 125 lbs, you really don't have a weight problem, as that is what is proper. Isn't that what is at the root of this question?