Depends on what your going to do with it. Take whelp date and add 6 months, then add 6 more months maybe 2 more. This will be the approximate time it takes to get any dog through the Basic Program. A dog welled in November will be approximately 6 months old in may of 2013, which is the worst time to ever start a training program in the south but if your trainer goes north for the summer it works. Of course none of this matters if it's going to be a "Rock Dog".
My pup was born 11-11-11 and boy was it a task Force Fetching in the summer. It's hard to train a lab in South Louisiana heat but not impossible. You'll have to pick the time of day you train.