LIH,
I've got the same problem. I used to be deadly accurate out to 30 yards or even further with iron sights on my old Blue Streak, with 17 year old eyes. More hits than misses on head shots only.
Nearly 30 years later, I need good light to hit a sparrow at 12 yds using iron sites. Sure, I made some longer shots at distance with iron sites, but if it was overcast, I doubt I could make a 3" group at 20 yds.
The scope isn't just nice, it's imperative for older eyed folks. Our depth of field just isn't there anymore.
Mark