What do you want to train your dog for? What do you mean by purebread? Pure hunt test lines or 2 labs bread together? What are their respective titles?

It is never to late to train your dog. I am guessing that you want a good hunting companion.

Buy yourself 10 minute retriever by John and Amy Dahl and or Tri-Tronics Retriever Training by Jim and Phyllis Dobbs. They will get you on the right track...pick a formal training program and stick with it......DO NOT TAKE SHORT CUTS!

Being that you are getting started a little later than most, you will have to spend more time with your dog on some drills than if it were a pup.

Good Luck and Good Training!!