While I think that doing some of the things that are mentioned makes sense, and I certainly think that having her vision checked for her ability to see in colour, I don't think that following a formal program with a 3 year old (older or younger 3?) is necessary.
Better to spread out your attention and engage her in observing and learning from the environment. Certainly colours are a part of that, but pointing out stop signs as you encounter them and asking her to identify and point them out, or people wearing hats, or trees with flowers or fruit or people walknig dogs are as much a part. Get colour/number/rhyming picture books from the library or bookstore and read several daily. Watch Sesame Street on TV or DVD/video. If she likes workbooks, get a general one for preschoolers that covers a number of subjects and let her do a page or two now and again.
edited to add, far more boys than girls are colour blind, and there are different types of colourblindedness.