I'm not good at vent sexing myself but it looks to me like you did a good job. It really does appear to be female. Perhaps someone who does vent sex their birds can confirm?
According to Metzer farms embdens can be sexed fairly well by down color at hatching. The grey down on the males is lighter then for the females. Its a bit hard to tell, yours looks fairly pale in some of the photos and darker in others pictures. How dark was the back down color when you got...