If I learn HTLM, CSS, Javascript, Jquery & PHP would that be a good basis for learning papyrus and other modding languages?

Would learning these languages be a good way to get better at modding?

Knowing a computing language previously doesn't hurt, but most things in Papyrus are pretty straightforward and a lot simpler than most languages.

Those aren't programming languages though, but Javascript is a OO web-based language and would give you a bit of a head start with papyrus when it comes to the Object-Orientated side of it.

But it's not mandatory. I started out with ZERO programming/scripting language experience.

Unlikely. It'll maybe make it easier to pick up but trying to learn them and then learning Papyrus is pointless.