Am I failing as a new mom because my October' 2015 baby hasn't hit all her 4 month milestones?!

I have been placing my Little One on her tummy for tummy time and she has gotten stronger but she doesn't respond to her name, or turn to look at us like most milestones say. She doesn't do baby push ups either. Im a Stay at home mom so majority of the time I am playing with her but to get ready cook or clean I place her laying down on a rocker. I just feel like maybe I need to constantly be entertaining and be a teacher for basically the 12 hours she's awake, all day and then I will see these milestones being achieved. Or am I ok?