You can get pierced immediately at about 4mm or so, scapelled to higher. Go to a decent studio though. If you want the eyebrow thing, I can''t emphasize enough, GO TO A GOOD STUDIO WHO HAS DONE SURFACE WORK A LOT, make sure they use a metal surface bar also, which they should. If not, it will reject, and you will lose your eyebrow, cos the hair won't grow back there. If you go to a shitty place, they will use a standard bar, and it won't be there for long. Even if they use a proper bar, its much more likely to stay in if you go to someone who's done them a lot before, surface piercings aren't really the same as other ones, you can't bodge them.