The best programming language is one that you'll start using right away to write programs.
I'd suggest Python as one good choice. In the last decade or so, Python has become one of the most popular teaching languages, so there's a lot of support for learners in the form of books, websites and video tutorials.
Khan Academy uses JavaScript in their "Introduction to Computer Programming" videos. The primary use has been in scripting of web pages, so your programs are usually run by a web browser such as Firefox, Chrome or Safari. It takes more keyboarding to get your first program to run, but you have a quicker path to nice graphics, and a language that can run on any computer, tablet or phone. Lousy for file system unless you get a standalone interpreter like Node.js (and that loses the graphics and "run anywhere" that the browser provides.)
The AP Computer Science program for US and some other high schools uses a subset of Java as their teaching language. If you're still in secondary school and planning to take that course in the future, you might want to hold off on using that as a personal starting language. Otherwise, you might be bored enough by the language part of the course that your grades will suffer.
Those are three popular choices for beginners. There are also languages designed specifically for teaching programming, such as Scratch or Alice. Google if you're interested. I find that those things tend to support some particular professor's teaching style and take a lot of set-up work to get installed and to get answers when something goes wrong. Not so easy for the independent learner.
One thing that I think is important: Get a computer with a developer-friendly OS: Windows, Mac or Linux. It doesn't have to be a bleeding edge game rig or anything. A real keyboard and a decent amount of screen space are the most important things you'll need, along with an OS that doesn't mind users writing and running their own programs. (Android, iOS and ChromeOS are for users, not developers.)