Gaining weight?

I have no problem gaining weight, I’m 5’3 and weigh 100-105 depending on the day but in a span of three months I can go from 105 to 120, no problem. The only thing is that its never noticeable weight, my family always thinks I’m the same size I’ve always been! I have a decent sized butt for my size, I just don’t have wide hips so it looks kind of odd. Is there anything I can do to get wilder hips?