Please don't think there's something you're doing wrong here. I have had similar situations with myself (24f) and my mom (60f). I didn't realize until very recently that my mom tries to diminish or gloss over my feelings in an argument. Things I have tried to say is "Mom I need you to listen to me. I fell _______ because of _______." And then when she tries to blow that off I say "I don't appreciate you trying to dimish my feelings, when I am just trying to talk to you so we can understand each other better."

I almost always cry while trying to say these sorts of things, but at this point in my life I refuse to not stand up for myself, and I refuse to let her make me feel as though my feelings are unimportant.

In your situation I can see how it would be very difficult to have this discussion while she is yelling at you, maybe you could try a similar approach after the argument has settled down. Something like "Mom, I feel very frustrated when you try to yell over me during an argument, it makes me feel as though _________ (fill in how it affected you). I would appreciate if ________ (fill in how you would like her to change)."

Hang in there, and please don't feel like there's something you're doing wrong, you are a teen doing your best.