I say it is yeh. Theyre all different and do things at their own pace. My sister's first always had a smile on his face and her second didnt hardly ever smile. Im not sure when his first smile was but i know for months of him being born i never saw a smile. Half the time he didnt even blink either. It was just him. And now he's 4 and a half and a very alert and happy smiley boy