the question that should be asked is not whether the light was green for you when you hit her, its what the light was when she started crossing.
a green light is not licence to run over someone who fell on the street when they were crossing legally, for example.
From looking at other pedestrians, it looks like the light just turned green. You should be looking before proceeding.
its also just unwise driving to speed past a vehicle that is blocking your vision and almost stationary like that. Its an easy way for someone to turn left in front of you, even though this time it was a pedestrian.
In short, I actually think its your fault.