Two suggestions: Lamy Logo, same nib as the Safari etc but a slimmer, metal, body and a pull-off cap. EF is good for notes (more equal to a Fine in other brands); very reliable writer
Or Platinum PTL-5000; slim body, pull-off cap, large capacity converter, and very smooth 14K gold nib with the advantage that it's a reliable if slightly scratchy writer using the back of the nib - that gives a very thin line, great for annotating texts. Another very reliable writer even if it's been left for a while.
The Logo is probably more rugged for school use, but the Platinum is the better writer!
Thank you for the suggestions.
As just a pen to annotate, I think the logo would be more adapted.
But now I think I will go for a Prera,
Thank you !