Most Helpful Guy
Style is used to project an image of yourself. When I was your age, I also wore combat boots, plaid shirts, surplus army pants ripped off at the knee, etc. The music you listen to, the style you have etc are your 'tribe' and a big part of your own self identity. Music _was_ important to me then, I played in bands, and it was a big part of my life. My wife liked overlapping music, and I guess though I was cool.
Now I wear more suits and sportsjackets. I had a 5 minute conversation with a guy I bumped into in an elevator yesterday about northhamptonshire shoe makers and the best web portals to get them through. My wife, who used to wear all black all the time, drools over summer hats in the brooks brothers catalog. The main music in our house is children's songs (though I did listen to a little Ministry on my commute a few days ago). Things change.
I guess what I was going to say is it sort of matters, and at your age its naturally a big part of your self identity.
As for the last part of your question, yeah, you definitely are more likely to approach people whose dress suggests they are part of a similar 'group' to you. I wouldn't say it makes her more appealing or would make up for looks - my sense is women put MORE stress on 'appropriate dress', men are more interested in looks. However if I like her looks AND her style, it is a plus, and I might ALSO think I'd have a shot.
It would be weird if I were single now, because well, I'm walking down the street in a suit, my piercings are gone, no more shaved head (or long hair partly shaved head). But when I see good looking 'indie' or whatever you want to call them girls out of the corner of my eye, my brain has forgotten I don't look part of that scene any more ...