First off, wsc, don't worry so much about forming a group, unless you're one of those David Koresh types. Nothing makes a person look goofier than when he/she is trying too hard to fit in. Just be yourself, and other like-minded souls will find you, and vice-versa.
Do SOMETHING extra-curricular. Whether it's a club, sport, student gov't, whatever. If it's something that interests you, go for it, and don't take crap from anyone if your thing happens to be the chess club, model airplane club, needlepoint group, whatever.
OK girls. Unless you're the star football player, artsy-musician guy, or someone who somehow manages to avoid all the acne, braces, and lack of confidence that usually accompanies adolescence, you ain't getting laid anytime soon, and that's OK. Get a Penthouse and a bottle of Jergens, and relax, the babes will come eventually, unless it's junior year and you still aren't using deodorant and pick your nose in public.
Embrace the awkwardness and nerves, it's completely normal. Just try to not worry about what anybody else thinks. I know, this is one of the hardest things for a high school kid to do. But, if you stick to trusting yourself and follow your own desires and instincts, you'll never regret it, regardless of the fact that your love of ham radio gets you a wedgie every thursday.
A very nice, well thought out answer, follow what you can of that.