There is no way you can do this. A girls hips become wider because it is her body getting ready for her to have kids, not that I recommend having kids at your age that is for sure. But that is the reason why. Girls generally have bigger butts than guys to. This is all normal and is very much liked by guys, some other women are also jealous of women like you. :)
Unfortunately, my love, your bone structure is your bone structure. With the possible exception of shaving your hipbones down, there's very little to be done on that end. I really do not recommend shaving down your hipbones.
Why would you want to do that? I think your hips look lovely the way they are. The way the female body narrows at the waist and flares out at the hips is so distinctively feminine and beautiful. Why would you eliminate that?
You can work on the weight that is carried in the hips, but there is no way to reduce the overall structure of the hip bone. I like wider hips personally, I think they give a more flattering figure - but to each their own. I wouldn't at all worry of it, I think you have a very nice figure just the way it is.
My body shape is similar to yours. Actually my hips stick out even more. And there's nothing wrong with it. It would be boring if we all looked the same, right? In my opinion, you'd look even better with a dress that follows your shape, that is fitted on top and flares at the bottom
If you're wearing something tight like that try some shapewear underneath to tighten it in a bit but really you can't change your bone structure. Sure in tight dresses it might not look the best but naked? I'm sure you look better with wide hips.
I've always hated my wide hips too but honestly you have what you have
You might think right now that you don't like them because trust me, I'm in your position and I know the can be a pain but you'll love them when you're older. Body modification is not a good idea at all. Especially for your hips. Hips are needed to help carry a baby while your pregnant so you should almost be thankful for them