Once you feel you have your arms around Java and the fundamentals of programming, I'd suggest spending some time learning about databases. It's pretty critical in a whole lot of programming areas, and having database experience under your belt should be a huge head start.
Also keep in mind that volunteer work will go a long ways on your college application. If you can't find a paying job, you might see if there's a way you can provide some programming services to local non-profit orgs. I suspect web development would be appreciated and more tangible than asking them if they need any Java apps, but maybe you can find a match. Their eyes should light up when you offer to work for free
Good luck on your college entry, I agree with the rest, it sound like you're off to a great start.