Can you shampoo your hair the same day as dyeing it?
The only reason that you might want to do so would be to tone down the colour a little. Your hair should have been shampooed the day before, (according to my hair colour directions), and it doesn't need a shampoo after using the colour and the conditioner.
The directions I follow with the hair color kit I use rinse the color out then use the conditioner provided. I never shampoo it before using the conditioner.
You should wait at least a day before you shampoo, unless you're trying to wash out some of the color. If not, be sure to use a color-safe shampoo.