My experience, females don't respond as easily as the males. But it could also be the breed. I had a Shiba inu mix female that wanted nothing to do with my son. Later on I read that they aren't really good with kids. Although she was actually fine with older kids, but the crawling baby... She wanted nothing to do with him. She snapped at him and that was all I needed to see! She was gone within that month.
The male Doberman/sheltie mix would let my son step on his ears and he wouldn't even flinch. He loved the baby!
Our spaniel, Ladybird, is about 3 and is also our first baby. We've been working with her for a few weeks now on getting used to the baby stuff. We play the music on the swing for her, we say the baby's name to her, we played a baby crying/laughing/cooing on you tube to see how she would react. We also have been working on commands for no barking and off/away. So far so good... I've also heard it's good to bring something of baby's from the hospital for her to smell before baby actually comes home. Good luck!
I am worried about the same thing. I have a year and a half year old labradoodle. He is very loving and very attached to me. I have introduced him to things the baby will be in. For example, we set up the bassinet, swing, and nursery early so he got used to seeing them. I also read that playing sounds of a baby crying helps dogs adjust