I personally am not much into time deadlines. Weight loss just isn't that predictable, even if you never miss a step. And, we're all human, we all miss steps
. That's why I'm really into the 5-Pound Challenges. It doesn't really matter to me that someone else always wins (I lose to slow at this point). It's just that it keeps me focused on one small, reasonable goal at time ... just the next 5 pounds. And even if I don't lose 5 pounds as fast as someone else, I still see my start and goal weights going down over time, and that keeps me excited.
OTOH, I do participate in a couple time-related challenges. On the Vegetarian forum, we've been doing holiday related challenges. But that's OK because at this point, I can handle it if I don't reach that goal on time. It's just for fun and support. It's just an extra thing I participate in, not my major focus. You have to decide whether that would work for you, or just set you up to be frustrated and unhappy.