I'd suggest to learn well the .NET concepts (garbabe collection, assemblies,
reflection, strong names, interop), the huge .NET Framework class library,
the VS.NET IDE, the OOP principles, refactoring, good programming skills,
etc., all of this language-agnostic, and once you master all that, learning
the syntax of C# or VB.NET will take you only a month. You can learn both
and use the one which you like more, or the one that you are told to use.

In the .NET world, the programming language is a thin layer on top of all,
and it the last thing to choose. Just my opinion, of course.

C# is not a career, any more than a hammer is a career. The first thing you
need to decide with regards to a career choice is, do you want to become a
programmer?

A programmer writes software, using one or more programming languages (such
as C#) as the tools of their trade. In fact, these days, it is more likely
that a programmer knows several programming languages. For example, if you
specialize in web applications, you will need to learn a server-side
programming language, client-side JavaScript, and be familiar with HTML
(which is not a programming language, but a markup language), XML, and
various web application-related technologies. Almost every developer needs
to know the SQL language (Structured Query Language), which is used to
execute procedures in databases.

So, assuming that you want to become a programmer (excellent choice if you
love math and logic), your next decision would be in regards to what sort of
platform you want to develop for. Again, assuming you want to develop for
the Microsoft platform (after all, this IS a Microsoft newsgroup!), you will
probably want to learn .Net, although many developers work well below that
level, and work with Win32 programming, which uses C++, or (gulp) VB.
Possibly even as low-level as Assembler and/or C.

But let's say that you want to work with .Net. You have a huge variety of
software projects that fall into this category, and if you're not a
developer yet, you might want to start out at the more comfortable
"high-level" end of things, rather than bits, bytes and hardware, for a
start.

At this point, you may decide to specialize in a certain type of appliction,
although this is likely to change over time. It is not that important, as a
program is a program is a program. So if you can develop one type of
program, you can develop another.

NOW you're ready to pick the first language you will study. And at this
point, I would recommend C#. It is more powerful than VB.Net, and less
forgiving. Being less forgiving, it will teach you to write more solid code.
Starting from a foundation of solid coding technique, you can easily work
with VB or other languages as well.

Once you have fairly well mastered one language, you're well on the way to
learning others. Unlike human language, programming languages are basically
all the same, except for syntax (and a few other things, such as the
capabilities they afford to the developer).