I am new to this coding world. Recently I have started with Turbo C/C++.
Turbo C++ is
ancient. C++ in particular has been revised in several important ways over the last fifteen years, and is about to be revised again. You'll eventually find yourself learning things that just won't be true when you get to a modern compiler. Try to find something newer if you can.
What next should I go for c# or java?
Just get comfortable with programming
generally before you start asking things like that. That's a little like asking, "what sort of vehicle should I buy next, bicycle or a rowboat?"
Actually, between Java and C# it's a little more like asking, "should I buy a bicycle or a Microsoft DuoWheel that looks suspiciously
like a bicycle in all important respects, but only operates well on Microsoft-branded bike paths." That's not really relevant, though.
The point is, it depends on what you want to accomplish, and what you want to accomplish right now is getting comfortable with the idea of solving problems in code, not the syntax of any one language. Those are skills you'll be able to take with you to learn any language, which you will be able to select later on the basis of how well it helps you get something specific done.
Are their any online tutorials available through which I can start by myself?
There are online tutorials for
every language. I won't point you at them because I'd have to Google for them, same as you can.
Also, we do have a
Programming Forum that gets a lot of neophyte traffic.