I'm 60 and although I've commute-cycled most of my life on upright cycles, it's only been shortish distances. I bought a Trek 7.2 hybrid as I now live in a fantastic cycling area with lots of hilly bits and I want to enjoy some of it on two wheels (and get fitter). I bought the Trek as hubby has one and I liked the ride that gave, but I rode mine around for 6 weeks while I got a feel for the fit and although it was comfortable to ride I felt the saddle needed adjustment but wasn't sure if that would affect other stuff. Rather than try and mess about with it myself I booked a bike fit at the LBS in Redruth (they do them free for bikes bought from them). The guy was very thorough, raising the saddle an amazing 5" and moving it back and tweaking the handlebar and end bar angles and gear levers. There was lots of good advice about cycling technique and and plenty of time on the trainer and nothing was rushed. Sent out on a test run, immediately there was an improvement in my comfort and performance. On the way home I even overtook a bloke going up the hill out of town! (not something that happens a lot, I can assure you)
So I'd recommend a good bike fit. Well worth it.