I am newbie. I ride a cannondale Adventure 3. First few days it was jus riding around the block (a few miles) and then I did 20 miles at 14 miles/hr average speed. The major problem with riding in a paved trail is that it is difficult to keep the pace due to fellow bikers/walkers/joggers. I am going to try hitting the trail early in the day and see if I could avoid this.

I think riding must be enjoyable whether it is 1 mile or 100 miles. My two cents - it doesn't matter. You can ride only X (X = any postive number) miles all your life and if this keeps you healthy and happy, then thats cool!