Lol, you are so cute. I swear, it's like you're thirteen. (I mean that in an "it's adorbs" way, not in a condescending way.)
When people go for the "alt" look, they are ALWAYS doing it for a reason, or to send a message of some kind. They have SOME burning desire to life a live that is, in some way, non-mainstream.
This is more true with large-gauge piercings and large conspicuous tattoos, since those are the ones that can't really be removed -- i. e., they signify a PERMANENT commitment to being "alt" in whatever way.
So -- the question isn't really whether she'd be attracted to you. Dude! Girls like hot boys. If you are a hot boy, girls of all kinds will like you.
The question is whether (1) you can understand and empathize with her personality, and "get" her in general, AND (2) whether you are down with her choice of lifestyle, whatever that may be.
#1 is where she may test you big-time. If she is a punk rocker and you don't look punk at all, she'll test yr ass HARD -- consciously or otherwise -- to make sure you understand her, her values, and her lifestyle, and that she's not just a quick fuck for the sake of variety ("catching 'em all", sex style).
As far as #2 -- well, as an example, if she likes to take party drugs and rage all weekend long at concerts and suchlike, then, are you down for that? And are you down for hanging with her social circle, who (probably) mostly look like her and don't look like you?
If so, then go for it!
If not, then, be honest with yourself -- after you get to know her, but before you end up deep into a relationship where breaking up would suck ass.
(I'm NOT implying that all, or even most, alt girls are druggie ragers... I'm just trying to give you an example of something that's more likely than normal to be an obstacle.)
I personally think diverse couples -- whether they be black/white, fat/thin, old/young, or alt/square -- are cool and fascinating asf, because I know FOR SURE that they are looking beyond the surface and are genuinely *into* each other. And it's fucking awesome when lovers are totally into each other <3
So... You miss 100% of the shots you don't take, so I say go for it. But remember, you may need to prove yourself just that extra bit.
@takemaker You said you were into the alt thing for a while -- Lmk what you think.
@rjgraveytrain Interested in yr opinion too.