Earlier I had a really big argument with my mom. I snapped and hit her. She didn't say anything and went downstairs. I dont know if I should say sorry or let her cool off first
This should be a complete no brainer. Yes you really should say sorry and really bloody mean it. Also try learning what accidentally means as that isn't it. Be responsible for your actions.
@WiseCracker I understand self defense. I really do. But if you're just having an argument and nothing is getting thrown and no one is throwing hands, there is no reason for you to put your hands on the other person. Because as soon as you do that, it's not self defense it's anger. You shouldn't be putting your hands on people to begin with. We're not little kids. This is the real world. What's gonna happen if someone uses your logic and smacks someone else in the middle of an argument? They're gonna catch charges. Not to mention the fact that this is his mother.