Ginebra - "I am a horrifically obnoxious teenager and this will proper piss my dad off" was, if I'm honest, the main reason I started down the facial piercings path. (I was right, too, he went ballistic.) Between the ages of 15 and 21 I acquired seven of them. Still got them all at 27. No plans to take them out right now, because they're part of my face and I'd feel strangely naked without them, same as without my glasses. But I don't feel any urge to get any more - I'm not that horrible, messed up teenager any more (plus I started running out of bits of face).
There was also an element of reclaiming myself involved, which I've read isn't uncommon amongst survivors of sexual abuse. It was very important to me that it was my body and I was choosing what to do with it. Thinking about it now, I suppose it was easier to assert my ownership of my own body in the face of parental and societal opposition, than it would have been to assert the same by conforming and trying to look the same as all my peers. If that makes sense?
The thing that makes me 
is that, while you're asking a legitimate question, I'm not sure what you'd accept as a legitimate answer. Would "It's decorative and I like it" be enough, or are you expecting deep and meaningful reasoning? If you are, then I fear you might be disappointed, because for many people it's just a fashion thing, not much different to how many people choose to make up their faces in the morning. I'm interested in what motivates people to wear makeup every day, but the responses tend to be thoroughly lacking in depth, and basically boil down to "I like it, I'd look dreadful without it, I have to for work" or similar - in other words, decoration and societal pressure to conform. Same goes for the piercings, it's just pressure from a subset of society with a different idea of how people ought to look.
OP, go for it if you want to, it's your face! Couldn't advise which to go for without actually seeing your face though.