I'm a high school teacher, and I'd love to hear from some people who know Visual Basic well. I teach an intro programming class each year, and I currently use Python. I occasionally get students who have had a previous class in Visual Basic at another school. These students tend to think they already "know programming", but after two or three weeks in Python they start to tell me they're learning all kinds of concept…
Another reason I'd discourage it, is because the language is tied to the IDE/editor and is very difficult to do something without it. Also there is not opensource community around vb6 and there is not much code to look at or to contribute in github. Even if the 'new project' dialog offers you several types of applications the language is very limited to desktop applications and com components.
VB.Net is very good and modern language and it has some interesting features.
I'd rather introduce programming in a nix environment using the unix way, write a shebang here and pick the language you would like to use. Learn file descriptors, stdin stdout stderr, process exit status, pipes, etc. Learn to write small libraries and programs that solve very specifics problems.