I think it for me i would want a pup, but only because i have children and puppy's seem to do better with adjusting to children. My mother got a 2 year old rescue and had it for 21 more years and it bonded with her just wonderfully and just passed last Christmas.
My Cowboy was 6 months old when we got him but did well with the kids, but 6 months is really still a puppy
