Okay, maybe it's just me, but why are you even asking this question? You are only 17, hopefully you are not drinking yet, or at least not trying to on the ship. Imagine if you get caught and your parents find out, they paid alot for your family to sail on this cruise, be respectfull of the law and don't try and drink.
I did a few things I regret in my day too, but I didn't even think about drinking until I was about 19.
By the way, I do my share of drinking now... (43 yrs old) mostly beer, but I found there was really no time for drinking.
Just kick back and enjoy what the ship has to offer. Buy a crazy hat, you'll be the talk of the ship.
(See my photos under "Paradise to Mexico") We had a blast.
Carnival-Paradise Sept, 2007
Carnival-Pride Aug 31, 2008
Carnival-Splendor Sept 6, 2009