Hey Daniel. Try explaining to your mother in a quiet, peaceful manner, that you'd really appreciate it if she knocked or announced herself first, before wanting to enter your room. It's good manners. Or if she is announcing herself by yelling in a rude way etc., then ask her nicely to stop doing that please, it disturbs you. Just because you live in her house doesn't mean it's not your home too - it is. They brought you into the world, made you part of the family, so, they should give you equal respect as well.