Body fat does not have anything much to do with height or weight. Body builders have really high BMIs and they have very low percent body fat. Fashion models have really low BMIs and usually a surprisingly high percent body fat.

Percent body fat is weight of fat/total body weight. People with low body fat usually have a reasonably high muscle mass.

Also your level of diet and exercise is pretty important here. If you exercise a bunch but eat to much, you can be kind of plump - fit as all get out but plump. I have seen many very strong cyclists who were pretty pudgy. Or you can be light and have very little muscle so a surprisingly high amount of your total weight is fat - I guess all fat and bones. It is pretty tricky to get really lean and have muscle mass at the same time. I have known competitive body builders and they tell me that getting into top form (around 4% to 5% body fat) is very difficult. It is so hard that most only "peak" for competitions.