How long does frozen hamburger stay good for?

Back in December I bought some bulk hamburger and I divided it into a bunch of one pound bags then I used my vaccuum sealer to seal up the bag and I froze them. I'm just wondering if they're still good since it's almost June. The meat looks a different color than it does when it's fresh (when it's fresh it's a dark red but now it's a light red) but i'm thinking that's just cause it's frozen. Anybody know if it's still good and how long it's gonna be good for??