I agree with the other person, it can get super distracting when someone's messing about on their computer. Or Mac, should I say. Hehe.
Don't bother wasting your money. Someone I know from my local council has one and she regrets buying it hugely. The performance on it is terrible, and all she does is make spreadsheets and word documents and stuff. For the same price, you might as well get a decent MacBook
If you really need a small computer for class, I recommend, (SHOCK HORROR!) getting a Windows Notebook PC. For the price of a MacBook air you can get a small PC with oodles of power, and you can still play games and movies and stuff on it if you want but it's still compact.