Welcome aboard, Old Rookie! Sure, some things have changed. But you can also find some of the same kits Monogram, Revell, Aurora, Airfix, and others, had out in 1967.
When I got back into modeling, there were two changes that surprised me the most. Those were the rise and spread of aftermarket detail sets, and the disappearance of figures from kits. I was used to guys scratchbuilding details, if they wanted to add detail to a build. And I was used, from growing up (b 1964) on Monogram and Revell aircraft and armor, to having at least one figure in a kit. Fewer modelers seemed to want to try painting a figure, too, so figures were one more item that aftermarket suppliers provided.
Otherwise, what you knew before is probably still valid today. We are in a golden age of variety now, though. And with the Internet, you can talk to modelers around the world, not just the guys at a local shop or club, and you don't have to wait for snail mail replies.
I look forward to seeing your builds!
Best regards,
Brad