I would like to know why you want to paint it red ,seems extreme may I ask why?
When I was pregnant, I thought of painting my son's nursery orangey-red, so it would be more like the womb. That's pretty amusing to remember now. He probably would have taken one look and cried. That said, when I was 12, I had a room with gold walls (a pretty darn deep gold, too), red curtains, and a red rug. My long-suffering mother never said a word against it, and I LOVED it, though it probably looked a bit like a bordello. Deep maroon reds were popular in that recent decorating period when everyone was keen on their house looking like an English manor's library. I don't think I've read any research that says everyone is negatively affected by red paint on a wall, but I have seen lots of decorating articles that suggest a light hand when using a strong color. Maybe the color can be used on a bedspread or accents of other types (throw pillows) while something more neutral is used on the walls themselves.
How old is this child, and does she want her room painted red? And if she later decides she doesn't like it, how quickly could you paint it a more agreeable color?
Is there a reason you want to paint the room red?
Speaking only for myself, I wouldn't last long in a room painted that color. Maybe one accent wall would be fine, and the rest of the walls a less abrasive color.