19 starting ballet- becoming professional?

I am 19. 5'7" 140lbs (currently but that is changing) I am naturally flexible and my turnout isn't perfect but it is about 2 inches away. I have hyper extended, pretty fluid like arms. Slightly hyperextended legs (only slightly) and high insteps (that means the bottom part of your foot? Not the top, they don't have an incredible looking line) I sometimes feel like I couldn't be a ballerina because of my weight and because of my late start. I've had dance and gymnastics training when I was eight to ten and finished 6 months of ballet and jazz classes in a conservatory program. I have always wanted to be a ballerina but never got the chance. I want to now and I think I can but I don't get alot of encouragement. However my taikwondo instructor says that I have the potential to be a black belt and go into the olympics. Which makes me feel alot easier. I guess what I need to know is, do you think I have potential to be a ballerina if I start intensively training along with taikwondo? Both realistic opinions and just plain ol encouragement is greatly appreciated. :)