I’m not yet ready for Catalina, but is there any remaining excuse for not upgrading to Mojave?
How old is your machine?
At the moment High Sierra is the oldest version of macOS that’s still getting security updates. If you’re not at least on that, you should probably get there.
My 2015 12" MacBook runs Mojave fairly well, and that’s a pretty low end machine.
it’s a 2017 12" MacBook
Then I think you would be absolutely fine with Mojave. Be prepared for a bit of dialog fatigue, though.
Dialog fatigue on Mojave? Nah. Catalina is another story, especially at first.
Ok, Introduction To Dialog Shock, then
Anyway, my main point was that OP should have no performance issues with his machine and Mojave.