I commuted in the rain/sleet/snow last year without fenders. It's not the end of the world, but I am very happy to have them now! A cheap and efficient way to make it in to work without looking like you were playing in puddles. I would definitely suggest riding in the rain.(I do, without a raincoat, stupidly. I can't seem to find a decent, cute and cheap one). Rain rides are quite refreshing.
Congrats on joining the commuter club!