Why don't I have a flatter stomach than I do? [PTS!]?

Someone please explain. I'm 16, 5'2" and about 97 pounds. My waist is about 26 1/2" to 27", around there. I don't eat junk food, I rarely eat saturated/trans fats and refined carbs. I eat the same amt of calories every day. I do about 250 situps a day, I lift a bit of weights most days and I run/jog for 30 mins every day. I've done this for about 2 1/2 months, about. I still have the "pooch". WHY?