Commuting. Good stuff. That's not a bad distance. How is the route? I am sure you'll be able to tweak a bit as you get used to it.
I have been doing this particular commute on and off for around 6 years. It had been mostly "off" recently due to running focus and kids' morning schedules, I would have to leave too late to get into work at a reasonable time. but that should be better starting this summer.
This route is pretty good, mostly decent shoulders and a long section of bike path in Rockville, not too much traffic in the reverse-commute direction, but a fair amount of lights. I also like taking the rock creek bike path when I have extra time, it is a bit farther but much flatter and with fewer stops.