Well, the best piece of advice anyone can give is to get classes, but it seems you're already doing that.

The first "language" I could fluently code in was HTML. HTML/Javascript/CSS/PHP/any other web languages are pretty useful to have, because the odds are that if you end up working in programming you're going to have to code for the web at some point. It could be anything from web services to having a (possibly compiled) language output HTML code for consumers (such as Java + JSP or PHP). I daresay that of all of the web languages you'll encounter, the most valuable is PHP.

You probably want to learn some database languages too. If you learn SQL and then move on to PL/SQL you'll be pretty much set, and luckily they're very easy to learn as far as programming languages go.

As far as compiled languages go, you're definitely going to want to have at least three if you want to get into application development. I'd pick C and C++, with Java, as a good range. These days, enterprise software is largely written in C# (which I hate, but it's useful to know), so if you're going to be doing database stuff definitely learn C#. The upside of that is that C is a subset of C++ which is a subset of C#. Don't bother wasting time trying to teach yourself these languages, since you'll pick it up so much faster with the aid of classes teaching the principles of programming as well.

Then there are scripting languages. Ruby, Python, Perl, PHP, etc. These are often used for web development, however they also get used a lot for regular programming. If I have the choice I'll use Ruby over any other language without hesitation. Compiled languages tend to be very picky about syntax and will throw back errors if you miss a semicolon or forget to initialise a variable, whereas scripting languages usually have more relaxed syntactical rules which allow you more flexibility. The beauty of Ruby is that you can put in the semicolons and the initialisations and whatever else you'd normally put in your C programs, for example, and it'll still parse and run correctly. Scripting languages are generally slower than compiled languages though, since they must be interpreted before running, instead of just running the compiled machine code.

Pretty much what I'd recommend is to learn a scripting language, since they're fairly easy to learn by yourself and save the heavy stuff for college.