It's a completely normal thing for kids to do that and for first time parents to have that normal concern. Who is gone the most working? You or Mom? It could also be that she gravitates towards mom because of the natural bond that it all begins with. Being it a boy or a girl it would still be happening regardless. It good also have been that Grandma had a part in it. What I mean by that is I am sure Grandma loved on her a lot and your little girl naturally was around the women more than the males. Like others here have mentioned, just don't let it affect your behavior because kids can sense these things and just continue to show that kid your natural affection to her and don't overstress yourself with it. You have her full life ahead of you both. I am a business owner and part time at that too so that I can stay home the majority of the time raising our kids instead of a preschool or baby sitters. I have my own special relationship with my two kids and my wife has hers naturally. When she got home it was all about mom and not dad. Which at the time was totally fine with me because I was about burnt out at that point, lol. Then it switched back to dad. It's all good. Just make sure that you and your wife are both in agreement when it comes to whatever when raising your little one. For there is one thing that kids pick up on right away. That's learning to play both sides and yes, it can start at a very young age.