First timer - orange cookies

This girl got a lot of yellow recently .. I couldn't tell if it was normal fade or something else. I started to think maybe nitrogen defiencecy or something... but then someone said it looked like light burn. I moved my lights up and turned them down ... How do you know how much light to give? I'm waiting to see if the yellow goes down or maybe there is something else wrong. My poor girl. Please don't fuck up now.