My little guy is much younger, just coming up to 19 months. But his "best friends" both at daycare and at home are girls. Just his favorite people to play with right now.
Honestly, I wouldn't put any thought into at all. He sounds like a cute kid, and very socialized. Those are good things. To me it sounds like you are just letting him be himself, so good job momma!
Hummm sounds to me he is a Lothario in the making ...hey your Mom is absolutely right .....