Fun & Fitness over 50

According the chart in Heart Zones Cycling by Edwards and Reed, I am a level 1 bike rider.
Here are the criteria for level 1:
* Distance: Can ride 5-20 miles at moderate intensity ( i can do more than that)
* Time: Can ride 20-60 minutes w/o stopping (i can do better than that)
* Speed: Comfortable speed is under 14mph (uh-oh, that's me. try 11)
* Experience: Rode less than 3 hours per week in the past year (I haven't been biking a full year yet but since I started, I have been doing more than 3 hours most weeks)

Here is Level 2:
* Distance: Can ride 20-50 miles at moderate intensity ( i routinely do 24mi once a week)
* Time: Can ride more than 60 minutes w/o stopping (i can do that)
* Speed: Comfortable speed is about 14-16 mph (nope can't sustain that for an hour!)
* Experience: has ridden for more than one year (nope) and rides more than 3 hours/week (yup)

So the only thing keeping me from Level 2 is speed and experience.
Experience will just require time to elapse and I am working on the speed.
I'm ok with that. Just so long as I see some improvement over time.