Do it now and your only regret will be not doing it sooner :)
For Ubuntu/LinuxMint :
Ubunutu --> Gnome Tweaks --> Additional Layout options --> Make Caps Lock an additional ESC
Linux Mint --> Keyboard --> Layout --> Options --> Same
From the terminal : setxkbmap -option caps:escape
There are option to swap CapsLock and Escape too, or you can have CapsLock when pressing both shift keys and other worthwhile options
Actually, MacOS can do this out of the box with no extra software installed. It's in the keyboard settings
You can only map CapsLock to a single modifier in keyboard settings? Which is how I've always had it myself (caps->ctrl) but that's not what's being discussed here.
(That being said, if you're used to jk/kj/fd/jj/jf, many years of muscle memory would still take a while to erase...)