my first sommute was much the same way, no idea what to expect. I was at work, taking light rail and using the bike jsut to get tot eh station...well...i was stuck at work past light rail hours, and they idiots in HR took the couch out of the break room, so i decided if i want sleep I have to get home...man it was harsh, especially only biking for 3 months at that time...9 miles straight, pulled it off in 45mins..bad part couldnt sleep for 3 hours after thanks to adrenaline.