Don't worry, we'll love ya no matter how far you ride.
And don't think that your mileage won't increase if you stick with it. Two years ago I was straining my shoulder patting myself on the back because I was huffing and puffing through a whole 3 miles a day. Now my daily ho-hum ride is ~15 miles.
A couple other thoughts:
There are people here for whom a 50 mile ride is just a nice warm-up. Just tell yourself that they are nice people, really, and try not to think about it.
My "best" mileage days just kind of happen. I start playing tourist in my own town, poking about here and there, finding out where roads lead, and when I get home I'm amazed at how many miles I've accumulated, and how slowly I rode. That's OK, it's not a race, and I'm really starting to know my town.
Finally, there is an odd tradition of "riding your age." That is, riding say, 51 miles one day the year you turn 51. Some people insist on the day, but I don't, my birthday is in mid-summer, and I'm not suicidal. DH's comment this year after his Age Ride as we were hauling our tired bodies into the house was "I can't wait 'til I'm 100." I don't think he meant it.
Give big space to the festive dog that make sport in the roadway. Avoid entanglement with your wheel spoke.
(Sign in Japan)
1978 Raleigh Gran Prix
2003 EZ Sport AX