Setting aside some of the legalistic retorts, I’m fairly uncertain the OP had in mind: ”So there I was, just tooling along, not hammering it. The road was flat, the flags were still. The speedo was between 14 and 15. Where does this stack up?” Since he’s a professed newb, I suppose all the advice to ignore this metric is reasonably given, but doesn’t really help him gauge himself.
OP: Maybe this will help. I turn 60 this year. Been riding 800-1000 miles/month the last 9 months, all solo. I’m not training to get faster. I’m not training at all. But I was a life-long runner until I hurt my back 5 years ago. Not fast, but well-conditioned; always finished in the top 10% of my age group. These days, on that rare windless day in the middle of Kansas, when I look down I’m doing between 16-17. But I’ll maintain this pace for miles and miles until the headwind or hill arrives. Yesterday the winds were in the 8-10 mph range, and my average for a 104 mile loop solo ride was just a tick under 15. Today the winds were 25 G 35+; my 55 mile ride came in at about 12.5 mph. Basic arithmetic will tell you your average will always drop as the course (assuming a loop) gets hillier or windier. You just can’t get the time back you lose.
My guess is the recreational, lower mileage rider is a bit slower than I am. Serious cyclists can be quite a bit faster than I am, even more so if they are younger. Knowing how my running times changed from, say, age 30 to 55, due to natural age losses and if I’m “cruising” at 16-17 now, then your 14-15 strikes me as being on the slower side. But I know nothing about your age, weight, and fitness, either. If you’re new to the whole fitness thing, then what’s to worry about? If you consider yourself out of shape, then 14-15 will quickly climb as you develop your legs, heart, and lungs.
In short, most serious cyclists ride faster than you are now. That’s not to say some serious cyclists aren’t slower, but that they would not be the majority. As a corollary, as you become a serious, committed cyclist, you will definitely get faster. If your intent is fitness, just keep riding. If your intent is racing…I think you’re starting a bit further back than most.