I shampooed my hair, and I'm planning on dying it when it dries.?

So, I'm dyeing my hair with Revlon blonde hair dye, and i shampooed it like a half hour ago or so, and im planning on dying it a little while after it dries. I'm not worried about it drying out as much as im worried about it becoming discolored. My roots are a dark ash blonde, and i know what color they will turn out to be, but will shampooing it turn the outcome of the color a different color? i'm just afraid of discoloration..