I think it really depends on what you want to build with it. Are you planning on making an IOS app? Do you want to make a back end server? I picked up Go for

I think it really depends on what you want to build with it. Are you planning on making an IOS app? Do you want to make a back end server? I picked up Go for my side project for the server side, and it has been a great learning experience. I think if I were to do a mobile app, I might try Swift.