This is nothing to LOL about!
^Persona 4 is probably my favorite RPG (maybe even my favorite game), so I can definitely say that you made a great purchase. Granted, you definitely shouldn't go into the game with expectations, it will ruin the game for you. Even still, despite the fact that you already watched the anime, there is still a crapload of content (about 80 hours worth) that wasn't in the anime, and because of the differences that exist between the game and the anime, you'll still have a lot of fun with the game. Can't wait for Persona 4: The Golden, it gives me a good excuse to play the game again.
Also, whatever you do, don't watch the P4 movie. If you want to savor the experience, you'll refrain from watching or reading about it and just play the game. Trust me, you'll be happier that way.