It depends on where exactly you are going.
If you are going to large coastal cities like Beijing hair dye
, Shanghai or Shenzhen, you will be absolutely fine, young girls dye their hair all the time, it is not a big deal.
If you are going to smaller inland cities, you hair may stand out. I currently live in a medium size city in central China, I see girls dyed their hair red, brown or blond, but your shade of green is kind of rare. However, it is just rare, not weird, you won’t be frowned upon.
But in under-developed countryside, unnatural hair color is the sure sign of “bad kids”. If you were a teenage boy, you could even expect local brats to pick a fight with you.