@Hereturbie ,
There’s an option to change how many characters you have to type before the autocompletion appears: Settings > Preferences > Auto-completion > From Nth character. So if you want to not autocomplete on X characters or less, then set that initial typing to X+1.
(If you want it to only show you length>X words, but start when you’ve only typed a couple characters, sorry, that feature doesn’t exist. We have a FAQ on where to make feature requests.)