Hi TR -- best thing to do is give us the whole background -- can you check the "Are you new to EF Ladies Board - START HERE!" sticky --
Can you give us:
1) Your stats -ht , wt, bodyfat %
2) Your EXACT DIET - what you eat in a day -- e..g.
Meal 1: 8 am
1 whole egg + 2 egg whites
1/2 c oatmeal
Meal 2: 11 am
5 oz chicken
1 c broccoli
Also can you put that meal plan into a food counts program like
www.fitday.com - its a free online program that has most every food u can imagine already in its database -- when you put your whole day's meal plan into it, it will show you the total calories & macronutrient breakdown ( grams, % protein/ grams, % fat / Grams % carbs) -- then we can talk about what you are REALLY eating and look at ways to optimize it.
Also consider that you are growing still. "Sit ups" are not really that relavent to bodyfat in that area as you can't spot reduce - you can however drop your overall bodyfat and see those results. But also remember that the whole mid-section is where women tend to have greater concentration of fat cells because that's where estrogen tends to make it get deposited (its a survival mechanism specifically to protect and promote safe reproduction).
If you can give us that info and maybe more specific info about the exercise you do, i.e. not just "i run" -- but how much, jog or sprint, how far?, then we can give you some productive info to get you going in the right direction. It sounds like you are almost there, but need to tweak something to get where you need to get.