There should fit in a laptop. And of course all the other things you need for the university and for other things.
I'm male and should play a role, I'm 1.78 m tall.
Best a bag with a lot of space.
At Norma, there are currently cheap and simple backpacks for just 6.99 euro. But I would not want to transport a notebook.
My recommendation is Daikine backpacks. Cost around the 39 euro - 49 euro depending on the color.
The North Face has good backpacks with laptop compartment. I have the Borealis and am very satisfied with it. High quality, a compartment for all the little things → no pencil case necessary, a large compartment for large folder and two three books, just the laptop compartment (I used it for notebooks and the block) and a snack has still had room.
North Face, Eastpak