Help with losing weight

So I'm trying to lose weight. I weight 178 pounds or so at 5'3" and no its not muscle. I have a good amount of excess body fat and I'm tired of it. I tried on a dress for my grandma's funeral (she's not dead yet but really sick) and it looked absolutely terrible on me. I need to lose weight. I am unhealthy and need to make a change. I'm trying to do squats in my room and I literally cant. My body is not capable of that. How do you do that? Any tips? I know what to do diet wise but I'm just trying to do some in room workouts. I have a small room. Any help appreciated. Thanks. Oh and also I have soo many stretch marks. They are everywhere. They used to be just a little on my hips but now they are on my stomach, boobs, arms, legs, calfs, just everywhere. Has anyone lost weight and seen them fade a lot?

Thanks soda is actually a big problem for me and something I'm trying to decrease dramatically. Thanks girls