Saban,
You have posted a question about the suitability of C# on a VBA message board so I'm going to answer with reference to these two languages but bear in mind that any other language could be used.
The problem described is a relatively trivial programming exercise. Because the processing required to do the scenario described is minimal you could pretty much choose any programming language you wanted. In particular C# is a much more powerful language than VBA and is pre-compiled as opposed to VBA which is compiled at run-time. This means that C# is probably going to be in the order of 10 times quicker to run but when the program is going to take milliseconds (as the situation described would) then its a bit meaningless. If, however, your situation is changed and you are planning to process thousands of these situations simultaneously then you may start to find that processing speed becomes an issue.
The other factor to consider is the amount of time that the program will take to put together and how robust it will be. Basically this boils down to how quickly you can learn a given programming language to the necessary level to get the program running and properly debug it. If you have any programming experience then I'd recommend that you use what you know as there are no real speed limitations. If you have no experience then I'd recommend you try to use
VB or VBA as they are specifically designed to be easy to pick up and use.
Having decided on a language you're going to need some sort of reference book to teach yourself the basics. I can't really recommend one as I've never bought such a book but there are plenty around and I'm sure they all do a decent job.
If you decide to use Excel VBA, which would be fine for the situation described, and are stuck on a particular aspect of getting the program working post back here and we may be able to help you with a bit of code.
Maccas