Mine is 7 miles each way, takes 30-35 minutes depending on the lights, traffic, and the direction of the wind.
I'd consider anything over 15 miles to be "heavy". At some point, you have to consider the time spent. If I can drive there in 25 minutes but it takes me an hour by bike, I'm probably going to be driving.
To answer your real question, yes 41 miles a day would be pushing it if you haven't ridden in 20 years. Take a test run on a Saturday and see how far you can go. You may need to build up to the distance, or try a "multi-modal" commute, e.g. take the bus halfway.