1) I am 15 pounds overweight and out of shape.
2) I am lazy when it comes to physical exercise.
3) It is 100 degrees and 95% humidity in the summertime where I live.
2 is ---That which is odiferous and causeth plants to grow---.
3 would take care of 1 in no time at all. This is your chance to get physically fit, not spend ANY money on gas for work, and help save the planet just a hair. Especially when you say it is 3.3 miles, I mean, come on, guy! Oh, and you'd be riding in the morning, right? It's cooler then. And when it's time to come home, that's when you'll get your small amount of daily exercise.
Last summer, I biked to work. Over 11 miles one way. It lasted three days. On the second day, my tire sprung a leak on the way home. If the conditions of the roads and sidewalks were better, I'd be doing it again this summer. (It took slightly less than an hour each way.) And amazingly, I wasn't sweating when I got TO work. That cool breeze in your face feels awesome. (For comparison's sake...6'2", 160 lbs.)
3.3 miles? That's nothing.
Plus you wouldn't have to go to a spinning class.