Will Premier Work For Me? [Want to run Premiere Pro CC 2019 on a 10 year old Mac running Sierra]

It isn’t just Adobe. Both Apple and Adobe provide support and updates for only the last three major versions of macOS, which are currently macOS 12, macOS 11, and macOS 10.15. So if you sign up for a Creative Cloud subscription, and if your Mac can’t be upgraded to macOS 10.15 or later, the current versions of Premiere Pro and other CC applications will not install or run on your current Mac. 

If you sign up for a CC subscription and stick to the Premiere Pro 2019 that’s on your current Mac, it should continue to run…I think. If it does keep working, you would not be forced to upgrade. However, you have to be very careful to never uninstall that version and hope that it never requires a reinstall, because for the reasons above, the Premiere Pro 2019 installer is no longer available from Adobe. The earliest version of Premiere Pro you can manage with the Creative Cloud desktop app is version 15, and that requires macOS 10.14 or later.