My body fat percentage is 16% i'm supposed to be able to see my abs i don't, i'm 16 yrs old a boy, i'm 5'5 i weight 139 lbs and my waist is 31inches?

Not always: It depends on your fat distribution, muscle mass, and body type. For your age, it is more ideal to have a body fat percentage in the 10-12% range. TO get down to that, be sure to eat a healthy diet, eliminate soda, juice, fatty foods, and fast foods. Targeted exercise like ab crunches are not likely to help much.

Who told you that ?: Professional body builders usually run 3-5% body fat and a quest for "washboard" abs is seldom successful when you are >10%. You get there through a combination of nutritional change and workouts.If this is your goal you just have more work to do.