Rockstar usually advertises their games for roughly 7-8 months after the initial trailer before they release the games. At least that's what they've always done. We're looking at a summer release. Sometime during the summer, June-July. If not then, we'll see it for the big game season around October-November.
There's always the rare chance it's not slated for a 2012 release, but it's highly unlikely, since the first trailer came out a while ago. If it does come out in 2013 though, it'd undoubtedly be before Valentine's Day.
I pre-ordered this game the week they put it on here, but I'll probably cancel it if it has no first-person option. After trying out a GTA IV first-person mod on the PC version, I just can't go back to exclusively third-person.
"Today, we're proud to announce that Grand Theft Auto V is expected to launch worldwide spring 2013 for Xbox 360 and PlayStation 3. "Developed by series creator Rockstar North, Grand Theft Auto V takes place in a re-imagined, present-day Southern California in the largest and most thriving game-world we have ever created set in the sprawling city of Los Santos and for miles beyond - from the tops of the mountains to the depths of the ocean."