I have seen the complete series of The Last Airbender and also waiting for the 2nd Book of Avatar: Legend of Korra. But yet i haven't heard of who was and which element was the First Avatar. Is there any information about him/her?
Avatar Wan was the first Avatar, and he lived about 10 thousand years before Korra. He was succeeded by a firebender, implying that he was an earthbender originally, but as far as I know, it hasn't been specifically said if the cycle followed perfectly from the first Avatar to the second.