Like everyone has said, everyone develops differently. What you could do is get mega blocks, legos (if she doesn't put them in her mouth), etc. and have her sort them by color... even if she isn't identifying them. After she groups them by color, you can name the group for her by its color name. If she does that well, you can move to the next step and buy mini m&m's or jelly beans. If she identifies the color properly, let her eat it. That's what we did with my daughter 9 years ago (she's 11 now). She wanted to eat the "colors" so she learned her colors.