I remember when 6 miles was a long ride for me, about 2 years ago...then 15-20 miles, and now I feel like I wasted my time unless I can get out for at least 20-25. Lately been doing 30 mile rides with a club, and on Memorial day I hit a huge milestone...70 miles. Saturday im riding 100 in the Tour de Cure.
Before you know it, 20 miles will be your short ride.