Good question, Stefania!When we were 16, we tore down the wood paneling from our room and painted the walls black. When our mother saw what we had done, we spent the next day putting the panels back up. Good times. We can now see both sides of your story.
Have you considered perhaps using chalkboard paint in some fashion? We love the ideas the Better Homes & Garden Web site gives on just this topic, "Help your nonconformist feel special and make a statement everyone can live with by saying yes to black, at least in small doses." By pairing bits of black with other striking colors (vibrant greens, hot pinks) you get all the pizazz without the total funereal vibe.
Do you have any other ideas for Stefania?