backpack recos for poly/uni

hii, quite a random qn but im starting poly in about a month, was looking to get a new backpack but not sure what size is suitable!

i wanted to get the fjallraven skule 20L (42 cm in height) because i like the design but not sure if it could fit everything i need for poly. theres also a 28L (50cm height) version, but i think it’ll look big on me since im short.

what backpack sizes do yall carry for poly/uni? im looking to get one that is good quality so it can hopefully last atw to uni😭😭i heard that thrs not much to carry most of the times in poly but abit curious abt uni carry load 🙏🙏