Hey man,
Like some of the guys have already said, you're at an age where you don't have anything serious to worry about. Not that that helps, I remember it's an age where it's possibly at it's most frustrating!
The great news comes in two parts:
1. You're making a conscious effort to sort this part of your life out. This could have happened when you were 25 which would set you back a whole lot. You can get this sorted now (or at least improve it) and you still have college to go through (if that's your thing) and the easiest times to pick up girls (college parties etc). This is the ideal time to sort this out! Just follow the basic advice you'll find here (go out more, get used to it, practice and improve, work out what you're doing wrong etc...). In 6 months time you should be able to look back and think 'I'm more stylish, well dressed, confident and sociable'. You might not be a stud, but you'll be better than you were!
2. Generally, despite how much shit guys talk, most guys are fairly awkward and insecure around high school age. The whole point is that people 'come into their own' at some point, often around college time, and possibly later. When this happens you'll look back on these awkward days and be frustrated that you didn't capitalize on them more, but you'll be crazy happy that everything is finally coming together for you.
So in summary:
Work on improving yourself
BUT!
It'll happen naturally anyway, it's just good to help speed things along
