I am 68 years old and last year rode 8,450 miles. On an average ride I may climb 2,000 feet, I have stop lights, joggers, car traffic and
who knows what to tend with. If I ride in town that is exacerbated by any number of things and my normal cruising speed is between 15
and 20 mph but at the end of my ride it usually is 12 to 14 mph average. I can't imagine the cruising speed I would have to maintain
to hit 19 mph average.
If you can hit your bogey and still enjoy riding more power to you.