Hello there,
I'm an 18 year old woman but I'm also a bisexual, so I thought maybe I could answer this too. I believe that a woman with a large-ish butt and wider hips can be very sexy because of the shape it gives the woman...the hourglass type of figure can be very attractive!
That being said, I also find that a woman with a slim figure can be attractive as well. I'm not limited to finding just one body type good looking.