Won't wake to eat

My daughter is four days old and it's our first night home and she's not waking up to eat. I've been feeding her every 3 hours because that's what I've been told to do and she'll eat for maybe 10 minutes on one side and less than that on the other when she does eat (I'm trying to get her eating for longer).

I just don't know what to do to wake her up, it's like she doesn't want to wake up to eat and I feel like I'm doing something wrong.