If you want to RUN A STARTUP,
this is the language for you!

Run a startup
JavaScript

JavaScript is mainly used in front-end development to make sites interactive, but thanks to the Node.js environment you can now use it for backend development as well, which focuses on the logic of how apps work behind the UI. You must learn JavaScript if you want to get into web development anyway, and it's pretty easy to get started with the language. Much of the Node.js community seems focused on performance, so this makes Node.js a good choice if you care about performance as well.