Are little babies easier to birth?

So I was talk to my husband today about how I’m so tired. I said “I can’t imagine going another 2 months. The baby feels so big already” He then asked if I was going to break his hand giving birth and I said “ it depends on if it’s a 6 pound baby or a 9 pound baby”

I was thinking about it and I imagine the head circumference is what makes a difference and not necessarily the weight.

Are little babies actually easier to give birth to?