You really should be able to do more. If anything you are a bit underweight. Do some lifting.
Don't fight the wind for one thing, ride a different direction. That's the first thing I do every ride. Start going 40 miles. I don't see how you can't on that bike. Unless maybe drops aren't for you. I sure hate them. And find a quiet highway with shoulders. That's the only way to bump miles without getting bored silly.
Plus, we don't know how fast you are trying to go. You need to figure out how fast you go at 50 or 60% effort. Do that on long rides. For me that's 15 to 16 mph. + or - for the wind. Same on any bike, go as fast as the wind lets you.
27 miles is a rest day for me, and I'm 67. I go out for fast food meals 6 miles away, just for starters. Rain or dark cloudy days are the no go for me. But really, my city rides are more like 40% effort and basically sight seeing. Maybe yours are 80%. Not the same at all.
I have been doing less than many here, 3 to 6,000 miles a year. I did a tour to Oregon coast in 2018 on my 120 lb custom.
I was only 50 when I bumped up the miles when I had a soft job with fewer hours. I just went for a 10 mile longer ride every weekend that summer. Then in 2012 I changed to IGH bikes and really went up to 100 to 125 mile rides. For those I'm often bonked for 2 days after. LOL.
I ride anywhere, busy or not. Many are skittish about this, even the experienced regular riders. Get a MIRROR.
Last edited by GamblerGORD53; 10-23-21 at 10:36 PM.