Not much needs to be explained at this topic. The picture kind of speaks for itself!
If you girls are admiring women on Instagram and comparing your body to their bodies, or wondering how the Victoria's Secret models look the way they do all the time -- First of all they work their asses off.
But mostly it's about posing and knowing how to hold your posture to make your abs pop and your skin rolls disappear. ((The same way you pose in the mirror to make your booty bigger or your boobs stick out.))
Your skin needs to move the way your body moves. For example, sit up really straight wherever you're seated right now. Now tilt your body directly to the left. Do you have a crease between your ribs and hip bone? Sure you do, because you went from having your skin stretched out over your stomach in the up right position to bending over. Your skin needs to move with your body and therefore your skin needs to be able to roll over in certain areas of your body and that is NOTHING to be ashamed of.
With that being said, under your skin, my skin, everybody's skin, is subcutaneous fat. There is a healthy amount of fat your body needs to function and regulate body temperature. So the rolls of skin you can pinch with your finger and thumb has fat underneath it. In fat % estimations there is a measurement that can be taken called the skin fold method where you take a measurement device and pinch the skin. There is a healthy and unhealthy estimation of % body fat you should be in range of according to your height and weight. If you are wondering about what's healthy for you I'd advise you consult your doctor as they know your health history best.
Point being, be careful what you believe and what's driving you to get fit and healthy. You don't want to strive for unrealistic goals. Ridding your body of skin rolls is something I'd consider unrealistic, since it's kind of needed to move! Determine your goals based on what your body is capable of and what's going to make you healthy from the inside out instead of comparing yourself to another humans body.