Research macOS Catalina Feedback
The macOS Catalina betas offered a period of testing and with it, there is already a lot of feedback from users regarding macOS Catalina performance.
You can read up on this on Twitter and in forums where beta users shared feedback. You can also wait a few days and see how the final build is working for most users.
This will let you know how it performs on a Mac similar in age and specs to yours and how some of your apps work. You can check out the Apple Discussion Forums and MacRumors forums for more information.
This will help you understand if there are apps that are totally broken, missing features and other important info that you should know before you install the update.