I too am a teacher but my commute is only 2 miles to my school. I did however commute approximately 25 miles each way when I was in school (undergrad and grad) so it is possible. Things to consider would be your start time, how long it will take you travel one way, how much you have to carry, traffic patterns, etc. I commute to school three days a week. On the days prior to my commute I leave my clothes for the next day at school so that I don't have to pack and haul them leaving room in my panniers for my lunch (can't leave it at school for fear it will disappear over night) and my school stuff. When I commuted to classes I simply hauled it all stuffing my panniers to the max and even securing books to my rack with cords. Spend your summer training and look at all possible routes.