Yellow leaf . First grow

I wouldn't worry too much about the color at this point except to check the PH of your soil and get it between 6.0 and 6.5... Autoflowers don't like additional nutes too early in the game but that being said, since it's about 2 weeks old, you could start adding grow nutes at about 1/4 strength to get some nitrogen into her. It would be better if you had a diary for this grow and link any future questions you may have to that diary... that way, those who are trying to help you will have a fuller picture of what you're doing/have done and will be better able to suggest solutions. Good luck!