I've got the same high hairline you do, and I live in LA. I agree with the posters stating you need a better haircut. If you go shorter, the grey won't be as obvious. There are plenty of young dudes w/ buzz cuts, and short hair. Look in the fashion magazines and it's a common 'do.
But I strongly suggest not dying it. The dye job would make you look like you're trying too hard. Chicks laugh at dye jobs. No matter where you go, it always comes out too dark, unnatural, and easy to spot.