Ok, so I am really tall but sometimes I just feel kind of overweight, even though I may not be. On all the BMI calculators I've tried I've been overweight, or close to it. Here are my measurements:
Height: 5'6
Age: 12
Weight: 135-140, not really sure
Gender: Female
Other things: My body is pretty curvy, as in big bust and butt. Not crazy big though! I have lots of arm muscle, and about 1/2 leg muscle. I am slightly lazy... My only bad habit is snacking sometimes... please help!

Stop worrying. You sound normal, and you sound healthy. BMI can only give you a very rough idea of where you stand, and someone with a big bust and butt is going to be much healthier than someone with a big waist.

I'm pretty sure that all the supermodels get up in the morning, look at themselves in the mirror before they put on their make-up and say "OMG, I'm a flabby mess." Because even they don't look like the airbrushed pictures you see in magazines.

Be as active as you can, find a sport or activity you really enjoy, and try to keep the snacking as an occasional treat. Make point of eating everything off a plate, and don't obsess about your food.

Don't really understand your question. If you would like to lose some body fat, just stay away from sugars (cakes cookies etc), eat less of carbs and more lean proteins (fish, chicken, lean meat). Try not to eat carbs after 7-8 pm (a couple of hours before sleep). Drinks lots of water. If you like snacking - find some healthy snacks(fruit, bakes chips etc). Omit over-eating. Eat 4-5 times a day, but small meals - this will keep your metabolism up. Find some kind of sport that you like - walking, running, tennis - any kind of activity that you like and do it at least 3 times a week. Good luck :)