You can get arrested, and go to jail.
By the way, you have to have a valid drivers license. Any parlor that does not check for ID is NOT somewhere that you want to be. There are too many diseases to worry about.
The reason that you have to be 18 to get a tattoo, is because that is when your body stops growing. Getting a tattoo before you are done growing will only distort your tattoo.
So don't be stupid, wait until you are actually legal and then get it. I am sure that if you are able to pretend to be 18, then you are able to pretend to be mature and just suck it up.
By the way, Emily, not all piercings heal without trace of them.
If your parent is a good parent, which I assume that they are since they are making you wait until you are legal to get a tattoo so that you can make the decision yourself, then I really doubt they will let you off the hook without finding out who tattooed their underage daughter.
It's much more of a pain in the butt. Wait until you are 18 and save us all the headache.