I haven't tutored high school in 3 years, but at that time it wasn't common to get your *high school* textbooks in e-book form (unlike university texts). Typically, a text book publisher would glue a little insert into the back of the high school textbook that held a CD with the entire book in pdf form. (Nothing interactive, nothing more or less than the actual pages of the text book.) That should work just fine (in theory) on the edge as it's just a collection of pdf files. But, I've only seen this with high school math texts. You may not find this with some subjects like history, but you may very well find the novels/plays etc. you need for English class available (and the study guides, too). Of course, a lot may have changed in 3 years and maybe there's more variety now.
Does your high school make you buy books, or do they issue them to you? If they issue them to you, have you ever noticed a CD in the back? If you have to buy them, can you go to the text book store and check the books?
As for taking notes, you'll probably notice that you write faster than the notes show up on the screen, but at least the notes do show up after a second or so delay. They're there, you just can't always see them right away. I've noticed that the more stuff there is on the background of the page, the bigger the delay. So, if you choose a blank page as a background, the writing is pretty much instantaneous but if you have the graph paper as a background, it can take slightly longer for the writing to show up. It hasn't been a big deal for me.
I ordered the fancy pen everyone's mentioning and it's MUCH better than the included stylus, which is shorter than a regular pen/pencil but longer than a little golf pencil. If you need to be able to keep up quickly then I do suggest a full-sized pen. I find I hold the enclosed stylus a little more like a golf pencil than like a regular pen, and for long periods of time or quick writing, it might be awkward for some. I found one on ebay, but it would be nice if Entourage were able to include it on their accessory page.