C# @LucaMs, it is considered more professional than VB.NET
if you buy a €6000 camera it doesn't mean you'll be a good photographer.
same goes for coding (and other things). If you suck at it it wouldn't matter what language you use as that will reflect in your apps.
I also wrote 2 programs for a client and my sister. a counter program for a shop but with build-in client managenemt, customer card to get discount after certain buying, invoicing for the pro customers etc.
I did one in VB6 and another one in VB2010, the differences were kind of huge, a lot more than I expected.
These days when you install a VB version you are extremely lucky when you look for a solution that works from the first go.
They change a lot on syntax and properties that's what I hate about M$, why not stick to the same language and add features to it.