Am I wrong for being upset about this?

Me and my little sister have shared a room for 10 years. I've always wanted my own room but I know that's probably never going to happen any time soon. It's winter now and extremely cold outside. Our room is freezing and she said we can't have a heater in our room because then she'll be hot. Everyone has told me to just wear a onesie and some socks but I'm still angry. I know when you have a roommate you need to compromise but I'm tired of compromising. What do you guys think