I would just like to say that I only averaged 12.5 mph on my recent century ride, so it may be some time before I achieve this particular goal!
(In my defence - I did treat myself to some long breaks, made numerous photo-stops, chatted to other riders, and tackled some steep hills in the Cotswolds. I reckon it would have been 15 mph if I had been trying a bit harder and maybe 16-17 mph on flatter terrain. Still - the difference between 15 mph and 20 mph on a bike is huge. This year is all about getting back into cycling.
Next year can be a bit more challenging.
)