How Can I Tell the Difference Between Loose Skin, Flab, Cellulite?

I'm in my mid 40s, white, 5'5, 140#, 32% body fat. I'm noticing areas on my body where the skin is irregular (thighs) or the skin is crepey (hands, neck, elbow, chest), or it pleats if I run my fingers across the skin or pinch it (arms including forearms). I haven't been exercising like I used to and I've stopped taking the birth control pill a few years ago. My body feels mushy. How can I tell the difference from loss of elasticity, muscle tone, cellulite, flab?