What do you guys think of this bag? i wanted to get one for school this fall (I'm going to Parsons for fashion design) but I'm worried about which size to get: medium or large. I've been told that Nordstrom or ysl can get me the large; and the medium is in-stock at my local Neimans. What are your suggestions? I know some are opposed to using a designer bag as a "school bag" but I'm not expecting to be carrying really heavy stuff. And I'm in love with the inky blue color!!!! Thanks in advance!!!