Originally Posted by yuzu

I'll chime in since our situations are similar; same age, same flat commute and I just started this fall. Before that I've been pretty sedentary since high school. Mine is about 4.5 miles one way, takes me about 30 minutes depending on how many stop lights I hit. 14 to 16 mph average is pretty close, I can hold about 12 mph without over exerting myself and I hope that's something that will increase over time.

They way I figured out if I could do it or not was to ride my route on an off day. I had no problems going 4.5 miles and then turning around and doing the 4.5 miles back so 6 miles really shouldn't be a problem. I did pace myself at a nice steady speed, you can ride longer and farther at a slower speed than trying to sprint your whole way there.