Let me tell you something Abby, if your parents are doing something that makes you uncomfortable or scared go ahead and ask them about it. If she smokes every night you could ask her to slow down a little or even maybe ask her to go smoke outside Your parents are there to help you develop and understand things. I'm sure your mom loves you and doesn't know how much of a bad feeling it gives you.To clarify I have smoked pot before but don't smoke it any more and I also have friends back home who do it regularly. I'll tell you there are things out there that are worse for your mom. My simple advice would be to just ask your Mom about it and tell her how you feel. You should also ask people that you know don't smoke pot. This way you can find out from two different areas. The real risk of anything really happening to her is small as long as she doesn't drive or do things that need you to be focused. You just have to let her know that you care for her very much and you want to know more about what she is doing to herself. Maybe do a little research on your own before you talk to her and tell her about what you find. Whatever you do remember that Pot, like many other drugs do affect the developing brain and its very important that you don't pick up the habit until you're about 90 years old, because by then you don't have to wory as much.
In the end Marijuana does cause short term memory loss but that goes away.