I cant lose my little tummy pouch!?

I have been having the hardest time trimming weight on my lower tummy area. I have been doing crutches etc. Its weird because my legs are toned & my arms etc. but that dang pouch wont go away! Yes I excersise. I am testing for my red belt in TKD in two weeks if that tells you how I am on a "dedicated" basis. A good diet would be good too considering I have testing coming up & a Tournament coming up... I have tried almost everything!! Im a teenager if that helps with anything? I do not, I repeat DO NOT care about being "thin". Id rather build muscle then just drop weight till im nothing....That wont help me out in TKD at all. I just want to go back to being thinner in the tummy area that' all.