Replying to NS Store Question

i ordered a couple movies and sticker etc you know the whole deal. it was shipped, i still haven't received it, but i want to make another purchase but the stuff i ordered is still in my "cart". i was wondering if i  just delete the old stuff out of the cart seeing as it was already shipped without it messing something up. i know it's a noob question but i don't want my orders to get all confusing and messed up. thanks for any help