Like iistapp. I would suggest taking a certificate or two. CCNA and maybe even a CCNP, it's very 'Cisco' but i think it will give you a good foundation. And you can get some hands on experiences with routers, switches, asa firewalls and so on.
Maybe you don't even have to take the expensive certificates, you can just buy the books and use ciscos network visualizer.
As for VB .net i think it's fine for a 'beginner'. As long as it's .net and not 6
Then you can allwayes change pretty painless to c#, if you find it interesting. And if you manage to 'master' those two, you should have the mindset to learn other languages.
But then again, when you are that young and maybe not 100% sure what you want to work with. I would say, just mess around with as mutch as possible, and figure out what you really want to do. But it sounds like you are allready trying to do that