Depends what you mean by "knowing" C# and JavaScript. I also know C# and JavaScript, I'm definitely not an expert in either or even an intermediate (probably).

Depends what you mean by "knowing" C# and JavaScript. I also know C# and JavaScript, I'm definitely not an expert in either or even an intermediate (probably). I also know C, Java, Ruby, Python, HTML, CSS, Databases, networking, web apps, mobile apps, web services. I'd only class myself as above intermediate in a couple of areas and that is after 20 years experience working in software teams. You can build virtually any web app, client app, mobile app or service with these 2 languages, so ask yourself what you can do with these tools and probably whether you can earn a living using them. If you want to learn a bit about some other areas just do it...