How do i persuade my mom in to letting me paint my room?

I really really really want to paint my walls a subtle looking turquoise but she's not letting me paint in any color! I really want to change her mind. When I approach her I'm very mature and not whiny about it but she won't even listen she just cutts me off and says no not in my house. But my Dad is pretty ok with it. Will someone please give me some tips?!