After which meal do you bloat up the most? And have you always done that?
Generally speaking you have an extremely high carb diet going here with not a lot of healthy fats & minimal good quality protein.
The easy answer to your bodyfat issue is that your diet is the problem. I'm not saying it makes you a bad person or anything - I'm just saying that's you and how your body responds to your lifestyle. Me personally - I can't eat a pile of rice like that w/o bloating up. You may be carb sensitive or whatever - but I'd really say clean up your diet, increase the amount of good quality protein, add in some good fats - I don't know how much fat you get from the stirfry - but consider adding in some almonds in mid-morning or mid-afternoon or 1-2 tbsp natural peanut butter before you go to bed - not a shitload of PB - just 1-2 tbsp - its a good fat source but it can become really easy to turn into a "snack" where you eat half the jar in a sitting.
Which meals do you have control of - i.e. you don't have to eat what your family is eating? The dinner meal see if you can add in more protein & veggies & cut back on the rice to say 1/2 c. Break your meals into 5-6 smaller ones over the course of the day - like:
Meal 1:
1/2 c oatmeal or even 1/2 grapefruit
3 egg whites
Meal 2:
15 almonds
Meal 3:
4 oz chicken + 2 cups of veggies
Meal 4:
15 almonds
Meal 5: (your dinner w/ family)
1/2 c rice
2 c veggies
4 oz chicken or some other protein - not deep fried - lightly stir fried and not covered in sauce or something
MEal 6: if still hungry at night
1 tbsp natural peanut butter
That load of rice at night might be the source of your bloat. But generally it sounds like you are eating a pile of carbs (which is what your body likes to use first for quick energy) but you aren't actually using your body for any activity to burn up that energy source. So all it knows how to do is store it as bodyfat. Further your metabolism has probably become accustomed to your food intake & lifestyle - so it runs but not efficiently - i.e you aren't going to burn bodyfat w/ this lifestyle & diet.
I don't know what is the difference w/ your parents or other people and I'd actually suggest that you not compare yourself to other people because everyone is slightly different so you can't make assumptions about how you think other people's bodies "are" and then feel bad about yoruself because yours "isn't". Its your body -it runs a certain way that is unique to you - so its partially up to you to discover how it best operates.
I would definitley suggest getting more activity - that will help you deal w/ the stresses of school and the sitting lifestyle. I know all about that - I was a computer science major in college and regularly spent 22 hrs in front of a computer all day, every day. So just to let you know - we've all been there and we've all figured out ways to get more activity and change our eating habits to achieve what we want.
For you, do you have access to a gym or any classes through your school? An aerobics class? Pilates? Yoga? Those are fantastic for buildign up core strength - that is what you are talking about when you talk about being able to do a sit up- its the strength that is in your torso, your lower back, your connection across your glutes to your legs, your shoulders / upper body, back, chest, delts. If you get a good basic program going that will help you with everything - not just the ab stuff.
And then make a couple changes to your diet and you should see probably 5-10 lb of water weight drop off within 3 weeks. Basically your body is conditioned to eat a lot of those simple carbs and it just doens't run very efficiently. IF you cut back on some of it, increase your protein intake and a few extra good quality fats you are good to go!
I know it can be very confusing about how it all works - esp when you see other people who have these attributes like flat stomachs and all that. Just don't look at them and then feel bad about yourself - its a self-defeating exercise. Instead learn the basics of nutrition & training, understand how your body works and then make a few changes to your lifestyle to move towards your goals. You will feel soo much better in general and then when you start to see changes in your strength & your physique you will feel SOOO much more in control and much more confident in what you are doing.
I'd suggest that you read the stickies at the top of the board :
Are you new to EF Ladies Board - START HERE:
http://www.elitefitness.com/forum/showthread.php?t=388278
TOP THREADS - MUST READ!:
http://www.elitefitness.com/forum/showthread.php?t=363631
All sorts of good info in there.
I also recommend Bill Philips' BODY FOR LIFE book as an intro to how it all works. You can maybe check it out of your school library or find it at a book store anywhere. You don't need to get the version of it for women. The point is that the information and the diet program / training program are very good, very flexible and it describes how nutrition works. That will help dispell a lot of the diet confusion you probably have about how to diet and what you "should" have to do to get this body you are "supposed to" have.
And PLEASE feel free to ask questions here! This board is ALL about support and information so you can achieve what you want for yourself!