Yes. Wait a month.
If a baby is eating fine, growing fine, and seems happy, then one need not worry about him knowing about "night" yet.
By keeping the "night" dark, quiet, and without noise or activities; and making the "daytime" bright, with sounds, feedings, and activities; a parent can help his baby have a good, natural bodily rhythm. The baby will sleep
better at night, and behave happier during the day, soon.