1) Your teacher cannot learn a new language well enough to teach a bunch of high school students in time. Have some consideration for him.
2) Your goal when starting to learn programming is not to learn the syntax of any one language, it's to learn to solve problems using programming. - Learn about P-code ( or psuedo code ) - Learn about Simple Data Structures. - Learn about conditional( if-then-else ) constructs - Learn about iterative( for-while ) constructs, - Learn how to declare variables and initialize them; - Learn how to edit-debug-run code - Learn how to version-control code (any file in general) - Learn how to write functions/methods/sub-routines. - Learn how to comment your code for future debugging
These are fundamentally the same in almost all modern programming languages. The syntax changes from one to another is mostly cosmetic. The key is good coding and problem solving habits and attitudes.
3) It's easy to spend time on the internet and be anamored about a particular language, particular OS, particular editor etc - but in the long run, they are commodities; there's no great big differences between them
4) If you really want to work in python, do so. Finish your problems in VB.NET and re-write it in python. Just don't impose your preferences on your teacher and entire class. It would detract from the goal of the class.