if its 13.3" its obvs bigger than the 13" backcook, the bezzels are probs really wide making the screen look smaller maybe. And smaller isnt rlly that bad, who cares if ppl are laughing? ignore em if its portable and has a good battery life thats the most ideal for students.
If its that bad maybe considder buying a cheap monitor for your room, it helped me a lot plus it was easier to watch movies too.
are you sure u cant return it? normally stores have a 14 day return policy, no? ring them up and check to make sure