I have to write that because I"m running into folk that "run" web sites but are not web masters. They have no coding background but use nothing but plugins and control panels.
Yes, you should try to get by yourself but just like getting into the Indy 500, you'll need a few master mechanics on your team.
My website kepzone, here I use woocommerce with wordpress. Sometime my site take page load time under 3 second sometime it take over 5 second. How to control my page load ?