Hey, I just was able to breed a Blue Chocobo and a Green Chocobo, and they are of opposite sex. I know I have to breed them in order to get a Black Chocobo, but it says I must wait for them too mature. Most people say I have to race them to S Class, but to get my blue and green ones I didnt race them at all or feed them any greens... So how long do I have to wait for them to mature?

You dont have to wait a certain amount of time although winning races couldnt hurt, its more down to what type of nut you use

Also leveling/battling monsters for a few minutes usually does the trick.

i was shit outa luck, when i went to breed the green and blue, they were BOTH FUCKIN FEMALE!!!!
so ya, i gave up, i figure if that chinese dude can beat emerald weapon in a minute and 18 seconds...so can i...all i will need for that is a green choco..which shouldnt be hard