It'll be fine, your best bet would to be expecting the worst, but hoping for the complete and absolute best.
Teachers might tell your mom that stuff, but they won't throw you under the bus, I'm sure s/he'll maybe put in a few things to help out with and some ideas to help you. I think it's good your admitting to it at least, when you mom comes to talk to you about it, just be honest as best as you can.
As for the reading while you're writing, I don't see it as your fault when the teacher knows you do it and doesn't say a thing to you about it.
Besides parent teacher conferences aren't just all negative, they put in a few good words, maybe your good at something, or friendly, helpful, energetic, a good leader etc. I'm sure you'll be fine, those are just there to help the student improve and keep the parent up to date. Even if you get in trouble, it'll blow over and maybe will help you keep determined to get better grades.
Best of luck to you ^^