I've had a MacBookAir 11'' for two years now, and I also strongly recommend the 13''. The thing is, you're going to be sitting at school and looking at that small screen for hours and hours for several years, and 11' is limiting no matter how you angle it. Working with 13' will be much more satisfactory and practical, and the 13'' is also very lightweight and slim.
Get the 13'' is my recommendation.
Get the 13'' is my recommendation.