So I was going through Reddit and someone wrote that some things in ASOIAF were too modern for that era. Me knowing jack shit about medieval living wanted to ask if you could give me some examples about it? Thanks in advance!

The best example is medicine: unlike their medieval counterparts, maesters in Westeros have a working theory of antiseptics (vinegar, myrish fire, firemilk, boiling wine (although that wouldn’t really work), use bread mould as an antibiotic, etc.