I have the opposite problem, I have the wide child-birthin' hips, the joy... but anyway, getting to my point: a lot of times with my hips even if it says fits up to a size similar to mine it might actually not because of my personal shape because of, well, everyone being a little unique and my own proportions, most often I actually have no choice but to try it.
I'd have to suggest just trying it, or if not getting this exact one, get a similar one at a moderate price that you wouldn't mind paying to try it on and it's adjustable capabilities. To me from the description and photographs it does look like it would slink down small enough, though if you are super slender, like smooth lines and not quite a pear or apple shape in the hip/waist, it may slip down your hips no matter what you do, like a belt.
All in all be careful and double check the return policy if you intend to buy it just in case. I hope this was helpful, and if not I apologize.