It depends on what you are going to do with your knowledge. Would you like to program just for yourself or do you want to work in the industry? Do you want to build and maintain large applications, or do you want to get into web-applications (if so then you should learn another language) ,machine learning or just write some scripts? What I would like to say is: You should first know what you want to do with the programming tool and then you have to decide which language is most suitable for it. However, if you know the basics from one language, it will be easier to learn another. But don't forget programming is not just about coding.