I haven't read it myself, but I do recall hearing lots of good things about it. Which probably doesn't help much, but now that you've mentioned it I kinda want to read it myself.
That does sound like there's some possibility of that in your case, but by no means does that mean that their reaction would be garunteed to be kicking you out. High School isn't exactly the best time to come out anyways; most people have some growing up still to do, you're dependant on other people a lot more, you're not old enough to go to any of the fun places, etc. Now I'm not saying that I think people should never come out in high school, just that you're rather limited in options until later in life, anyways.
Yeah, fairly common phrase here too, it just startled me by how it sounded given the context.