Tattoos

Wait, Joe. Don't rush it, because you can get something shitty for cheap and regret it till the kingdom come. Same for stretching. You follow fads now... and they do change every few years. And you never know, perhaps you would want to become a Tory or something later on.

Eh, there's those who follow fads, and some who wanted it before it became hugely popular.
Ive had my ears stretched for 8yrs, and I know there's some here for longer. :)

But definitely do wait.

...also lying to your tattooist to get the work done is really bad form. The law won't support them at all if it's proven that you've given false ID. Not that you would do such a thing, I hope.

Save your pennies now because you'll burn through them pretty fast getting top notch work, and there's no excuse to settle for mediocre with the two plus years of enforced study and consideration. It might not feel like it, but you're in a great position to take advantage of looking around people's books etc.
Also some of the better artists can have years long waiting lists. So there might be a wait even after you're legal.

I didn't start getting tattooed until I was well into my twenties and it's never held me back.

+1.