I've already been cycling through winter (every freaking day of the year). Have to, if I want to get to school

And being in Canada it gets even uglier since most of the way to school is through an un-shovelled sidewalk through a park then a nice bike trail.
Only thing i'd really recommend is warm gloves and a chain guard <-
essential. Fenders good for those 0 degree days where it starts getting slushy