Is 12 miles too far? That depends. I used to live 16.5 miles from work, or 20 miles if I took the scenic route.
I rode about three days a week. I'm overweight and slow.
How often do you want to ride? What kind of shape are you in? How dedicated are you?
I now live car-free and have moved closer. I ride everyday, but my one-way commute is now 3.5 miles.