Well, lets clarify a few things.
1) Html is not a programming language. It is a markup language. Various tech stacks use it along with CSS as does your browser to represent a http message (the response side of that communication is your web page) among other things but that is the primary use. They build page structure and style respectively. Yes, some will argue these points. I do not care.
2) There are two primary types of coding environments in respect to web development. Server side and client side. It is true this line has been blurred somewhat with the wide adoption of Nodejs. Node is arguably one of the worst things to happen to the internet in a very long time. Just my opinion.
If I were just starting out I would start with any of the languages that share a C style syntax. Since it will make it easier to learn another language that shares that same code syntax style. Say Php and Javascript. They are very close in syntax. Go is another one that has very nice syntax that is more or less of the same branch.
I would also consider whether its a compiled or "run time" language. Start with a runtime language like Php or JS and get a good grasp of either or both before jumping into something like C# etc. Your knowledge base will have grown and you will have an easier time just setting up all of the tooling you will need to both write and compile the code.
Most importantly. Remember. It is learning a new language. Only with programming you have two master dictionaries. The one that holds the languages core API's (ie the Classes/Methods/Functions etc) and the one that you write (your application/program) to interact with them. Programming is the art of data manipulation. Start with the basics.
Most of all. Have fun =)
P.S. If you wanna get real crazy you could start by learning: