I haven't ridden since I was a teenager, now I'm 56. Been browsing the forums to learn before buying a bike. What am I waiting for? Actually, without going into detail, a major, very sad life-change in the next month or two, after which I will have a great deal of time on my hands, and I have promised to spend it wisely.
So far I've figured out:
. Get to know the folks in your Local Bike Store - buy from them.
. Figure out what kind of riding you'll do. (Initially errands, and weight-loss exercise - I'm a borderline Clyde. If I get into it again, touring, commuting.)
. Get fitted well, otherwise you won't enjoy it and develop that passion.
. Get properly equipped and dressed, same reason.
. Don't overspend to start with, expect to buy again after you gain experience and knowledge.
Still reading. Lots of smart, committed people here, I can see I'm in the right place.