Driving Skills

I've never considered myself a great driver - for example, with very little confidence in being able to perform a decent parallel park.  And I think driving in the US has definitely made me a worse driver.  Just for starters I think driving an automatic car is nowhere near as skilled as driving a manual car.  And negotiating the wide purpose-built roads in America is nowhere near as hard as negotiating some of the old, narrow, winding roads in the UK.  And I'm sure I've picked up some of the bad driving habits that I criticize American drivers for having.  But now that I don't need to commute to an office, I'm driving a lot less than I was.  And just recently I've noticed a few little errors creeping into my driving.  Nothing serious, and at least I'm aware when they happen as opposed to being dangerously oblivious.  But is this because I'm driving less regularly, or simply because I'm getting older?  It's a little bit disconcerting, and I hope just a blip and nothing to worry about.