3 months is pretty early for Bobs mating, and they may be establishing the pecking order. Most likely they won't actually pair off til next spring, as far as you might be able to tell, however I have had males become attracted to one female at 2 or 3 months old as well, however they were not actually a "pair" til the following spring. It seems to me that with Bobs, it is not just the female that chooses, or the male that chooses, but rather they both choose each other.