I haven't worn mine in a while, but I think depending on how large your butt is it might ride up some. Especially if you're doing any real bending over. But if you wear it with a pair of fun leggings or something, if it rides up it won't be anywhere near as noticeable.
Yes, it will definitely depend on your measurements. I bought the next size up just so it would be long enough to actually BE a dress instead of a top, so keep that into consideration when purchasing. Hope this helps.