K.H.
Men are much more prone to color blindness than women and even at that red/green color blindness is more common than overall colorblindness. (PS- I think EVERY mother worries at that age about color blindness...I know I did!!)
I'd 'test' her not with words, but with matching and/or pointing, especially where she can chose between red and green items. Hold a red and green crayon and ask her to point to the green one, as an example. If she can pick the green one from the red, I think you are good to go and no worries needed.