Your C++ starting point could help you get going. I've a lot of experience with VB, JS. PHP, SQL, but I've not done C++ or that kind of programming. So I learnt Lua from scratch and found it tougher going than it should have been. One of the problems was that it seems to be well-respected but only geeks use it. As far as I have seen it's only really used in World of Warcraft, whatever that is! As a result, there's not a lot of documentation or code snippets out there, and it's oriented to trained programmers (unlike VB or JS where you find all sorts of learning resources). So good mental exercise for you!
John