I second what @WayOutWestMom said in the above post regarding grade distubution and curves at the end of the semester even though the actual test scores aren’t curved. My D had a couple of difficult classes where she had resigned to getting a B in the class, but then when grades came out she was pleasantly surprised to have received A grades. She ended up with only one B in all of her college grades which wasn’t even a pre-med pre-req class. If you see that your test scores are on the higher end of the class, the end result will most likely be an A. Check the comments on ratemyprofessor to see if the he/she curves at the end, or ask some students who have already taken the course. Then make your decision. One W won’t impact your med school chances though.