...until now. What should I do? Was there a medicine or supplement my dog should take?

Biatch? I thought female dogs were called |3itches, not biatces

Labradors, sporting group dogs by nature are medium to large breed animals. The larger the size of the animal, the later it's heat cycle would take place. There is also a possibility that your dog is having a "silent" heat season. Best way to find out is bring your dog to the vet and have her smear test to find out.On the other hand, breeding is not for the newbie dog owner unless with the proper supervision of professional dog owners and breeder who can guide you in breeding your dog and whether your dog has the proper medical and physical attributes for breeding.