Contacted my hotel today, just to confirm, and I'm still good... Bumped it up to me arriving Wednesday as well. WOOHOO. A night of drunken revalry beforehand.
Clubs in Pittsburgh are 21 to get in FOR THE MOST PART, so I dunno that you'll be in much luck Famine. Just a heads up. Depends where you look... Some are 18 + in my neck, but not the vast majority, and those that are 18+ usually aren't overly popular, especially among the 21+ crowd.